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Encoding to h264 to save space

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cmisipster at gmail

Feb 18, 2008, 6:30 PM

Post #1 of 36 (5232 views)
Permalink

Encoding to h264 to save space

I am able to shrink 1 hour of video to approximately 150 MB at 200 kbit with
ffmpeg using h264. Seems to work well except with seeking. I wonder if
this is a keyframe issue. When I forward or rewind, there is distortion for
a few seconds and then the video fixes itself. If I forward or rewind
before the video is fixed, the progress bar seems to jump back. Seeking is
more reliable when the distrotion is allowed to clear first. Also, I cannot
jump to the very first frame of the recording. If I exit the recording and
play it again, I start on the first frame. Here is a copy of my latest
script. Single pass for now (hoping to go to 2 pass). I was wondering if
anyone could give me any ideas as to how to fix this issue.

Thanks
Chris

#!/bin/bash
VIDEO_DIR=/mnt/VIDEO

#subq to 7 trellis to 2 threads 2
#need to clear the cutlist and generate it again

function convert-to-h264 ()
{
#argument is file only (no path)
#need to dereference a symlink
inputfile=`ls -ld $VIDEO_DIR/$1 | awk -F" " '{ print $NF }'`

echo "Will encode $inputfile"
basedname=`echo $inputfile | sed 's,^$.*/$\?$[^/]*$,\2,'`
vidformat=`mplayer -vo null -ao null -frames 0 -identify "$inputfile"
2>/dev/null | grep "ID_VIDEO_FORMAT" | sed -e 's/ID_VIDEO_FORMAT=//'`

if ! [ "$vidformat" == "H264" ]; then
/usr/bin/ffmpeg -threads 2 -i $inputfile -acodec mp3 -ac 2 -ar 44100 -ab
128k -s 320x240 -vcodec h264 -sameq -flags +loop -cmp +chroma -partitions
+parti4x4+partp8x8+partb8x8 -me umh -subq 7 -trellis 2 -refs 1 -coder 0
-me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 300k
-maxrate 300k -bufsize 300k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 15
-qmax 51 -qdiff 4 -level 30 -aspect 320:240 $inputfile.avi

mv $inputfile $inputfile.old
mv $inputfile.avi $inputfile

echo "Building seek table"
mythcommflag --rebuild -f "$inputfile"

echo "Clearing the cut list"
mythcommflag --clearcutlist -f $inputfile

echo "Commercial skip to cutlist"
mythcommflag --gencutlist -f $inputfile

filesize=$(wc -c $inputfile | awk '{print $1}')
echo "Updating database"
mysql -umythtv -pmythtv -hmymythtv mythconverg -se"UPDATE recorded SET
cutlist=0,filesize=$filesize WHERE basename=\"$basedname\";"
else
echo "Already an H264"

fi
}

CONVLIST=`mysql -umythtv -pmythtv -hmymythtv mythconverg -se"select basename
from recorded where title like \"%$1%\";"`

for i in ${CONVLIST[@]} ; do
if ! test -L $VIDEO_DIR/$i ; then #its not a symnlink
#Check if this recording is done -mmin +5
filetoconvert=`find $VIDEO_DIR -name $i -mmin +5 | sed
's,^$.*/$\?$[^/]*$,\2,'`
if [ -z "$filetoconvert" ]; then
echo "$i is not finnished recording...Skipping"
else
echo "Moving $i to /mnt/VIDEO1"
mv $VIDEO_DIR/$i /mnt/VIDEO1
ln -sf /mnt/VIDEO1/$i $VIDEO_DIR/$i
convert-to-h264 $i
fi
else
echo "$i is already a symlink...Skipping"
convert-to-h264 $i
fi

done
[root [at] mygamep cmisip]# cat /usr/local/bin/RECconv2.sh
#!/bin/bash
VIDEO_DIR=/mnt/VIDEO

#subq to 7 trellis to 2 threads 2
#need to clear the cutlist and generate it again

function convert-to-h264 ()
{
#argument is file only (no path)
#need to dereference a symlink
inputfile=`ls -ld $VIDEO_DIR/$1 | awk -F" " '{ print $NF }'`

echo "Will encode $inputfile"
basedname=`echo $inputfile | sed 's,^$.*/$\?$[^/]*$,\2,'`
vidformat=`mplayer -vo null -ao null -frames 0 -identify "$inputfile"
2>/dev/null | grep "ID_VIDEO_FORMAT" | sed -e 's/ID_VIDEO_FORMAT=//'`

if ! [ "$vidformat" == "H264" ]; then
/usr/bin/ffmpeg -threads 2 -i $inputfile -acodec mp3 -ac 2 -ar 44100 -ab
128k -s 320x240 -vcodec h264 -sameq -flags +loop -cmp +chroma -partitions
+parti4x4+partp8x8+partb8x8 -me umh -subq 7 -trellis 2 -refs 1 -coder 0
-me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 300k
-maxrate 300k -bufsize 300k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 15
-qmax 51 -qdiff 4 -level 30 -aspect 320:240 $inputfile.avi

mv $inputfile $inputfile.old
mv $inputfile.avi $inputfile

echo "Building seek table"
mythcommflag --rebuild -f "$inputfile"

echo "Clearing the cut list"
mythcommflag --clearcutlist -f $inputfile

echo "Commercial skip to cutlist"
mythcommflag --gencutlist -f $inputfile

filesize=$(wc -c $inputfile | awk '{print $1}')
echo "Updating database"
mysql -umythtv -pmythtv -hmymythtv mythconverg -se"UPDATE recorded SET
cutlist=0,filesize=$filesize WHERE basename=\"$basedname\";"
else
echo "Already an H264"

fi
}

CONVLIST=`mysql -umythtv -pmythtv -hmymythtv mythconverg -se"select basename
from recorded where title like \"%$1%\";"`

for i in ${CONVLIST[@]} ; do
if ! test -L $VIDEO_DIR/$i ; then #its not a symnlink
#Check if this recording is done -mmin +5
filetoconvert=`find $VIDEO_DIR -name $i -mmin +5 | sed
's,^$.*/$\?$[^/]*$,\2,'`
if [ -z "$filetoconvert" ]; then
echo "$i is not finnished recording...Skipping"
else
echo "Moving $i to /mnt/VIDEO1"
mv $VIDEO_DIR/$i /mnt/VIDEO1
ln -sf /mnt/VIDEO1/$i $VIDEO_DIR/$i
convert-to-h264 $i
fi
else
echo "$i is already a symlink...Skipping"
convert-to-h264 $i
fi

done

beww at beww

Feb 18, 2008, 6:34 PM

Post #2 of 36 (5100 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

Chris Isip wrote:
> I am able to shrink 1 hour of video to approximately 150 MB at 200 kbit
> with ffmpeg using h264. Seems to work well except with seeking. I
> wonder if this is a keyframe issue. When I forward or rewind, there is
> distortion for a few seconds and then the video fixes itself. If I
> forward or rewind before the video is fixed, the progress bar seems to
> jump back. Seeking is more reliable when the distrotion is allowed to
> clear first. Also, I cannot jump to the very first frame of the
> recording. If I exit the recording and play it again, I start on the
> first frame. Here is a copy of my latest script. Single pass for now
> (hoping to go to 2 pass). I was wondering if anyone could give me any
> ideas as to how to fix this issue.

Can't help you on the seek problem, but:

What does it look like at that level of compression? I'd think that
150MB/hour would look like crap (technical term), even on an iPod.

beww
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myth at dermanouelian

Feb 18, 2008, 6:45 PM

Post #3 of 36 (5112 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 18, 2008, at 6:34 PM, Brian Wood wrote:

> Chris Isip wrote:
>> I am able to shrink 1 hour of video to approximately 150 MB at 200
>> kbit
>> with ffmpeg using h264. Seems to work well except with seeking. I
>> wonder if this is a keyframe issue. When I forward or rewind,
>> there is
>> distortion for a few seconds and then the video fixes itself. If I
>> forward or rewind before the video is fixed, the progress bar seems
>> to
>> jump back. Seeking is more reliable when the distrotion is allowed
>> to
>> clear first. Also, I cannot jump to the very first frame of the
>> recording. If I exit the recording and play it again, I start on the
>> first frame. Here is a copy of my latest script. Single pass for
>> now
>> (hoping to go to 2 pass). I was wondering if anyone could give me
>> any
>> ideas as to how to fix this issue.
>
> Can't help you on the seek problem, but:
>
> What does it look like at that level of compression? I'd think that
> 150MB/hour would look like crap (technical term), even on an iPod.
>
> beww

Agreed. I do 1GB/hour for my iPod recordings and they're beautiful on
my iPod and iPhone. Anything less and I can't stand watching it.
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http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

beww at beww

Feb 18, 2008, 7:14 PM

Post #4 of 36 (5101 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

Brad DerManouelian wrote:

>>
>> What does it look like at that level of compression? I'd think that
>> 150MB/hour would look like crap (technical term), even on an iPod.
>>
>> beww
>
> Agreed. I do 1GB/hour for my iPod recordings and they're beautiful on
> my iPod and iPhone. Anything less and I can't stand watching it.

Typical MPEG2 SD (a PVR at DVD resolution) is 2.2GB/hr. I'd thought that
at best going to h264 would cut that in half, any more and you are
losing significant quality.

Maybe the OP meant 1.5GB/hr ???

beww

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ron at ronfrazier

Feb 18, 2008, 7:16 PM

Post #5 of 36 (5090 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

> Agreed. I do 1GB/hour for my iPod recordings and they're beautiful on
> my iPod and iPhone. Anything less and I can't stand watching it.

Are you serious? 1GB/hr for an ipod? Thats only about half the size of
what I use for MPEG-2 SD resolution. If you are only encoding to
MPEG-2, I'd expect about 1/4 of the size. If you are doing h264, I'd
expect even smaller.

--
Ron
_______________________________________________
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mythtv-users [at] mythtv
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myth at dermanouelian

Feb 18, 2008, 7:22 PM

Post #6 of 36 (5101 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 18, 2008, at 7:16 PM, Ronald Frazier wrote:

>> Agreed. I do 1GB/hour for my iPod recordings and they're beautiful on
>> my iPod and iPhone. Anything less and I can't stand watching it.
>
> Are you serious? 1GB/hr for an ipod? Thats only about half the size of
> what I use for MPEG-2 SD resolution. If you are only encoding to
> MPEG-2, I'd expect about 1/4 of the size. If you are doing h264, I'd
> expect even smaller.

Oh, that's wrong. I checked the size of a movie that I thought was an
hour show. I go with 200MB/hour and it looks great.
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ron at ronfrazier

Feb 18, 2008, 7:56 PM

Post #7 of 36 (5111 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

> Oh, that's wrong. I checked the size of a movie that I thought was an
> hour show. I go with 200MB/hour and it looks great.

OK. Now THAT sounds reasonable. Here I was thinking you just had some
REALLY high standards :-)

--
Ron
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mythtv-users [at] mythtv
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cmisipster at gmail

Feb 19, 2008, 3:32 AM

Post #8 of 36 (5066 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 18, 2008 10:56 PM, Ronald Frazier <ron [at] ronfrazier> wrote:

> > Oh, that's wrong. I checked the size of a movie that I thought was an
> > hour show. I go with 200MB/hour and it looks great.
>
> OK. Now THAT sounds reasonable. Here I was thinking you just had some
> REALLY high standards :-)
>
> --
> Ron
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

Sorry, I seem to have pasted the script twice.

Its 150 MB an hour. My existing recordings are 1.5 GB an hour before
transcoding. I display to a 32 inch crt tv and I find it watchable. Of
course, everyone will have different standards of "watchable". It will
probably look horrible on any hdtv. Its excellent on my ipod touch although
my ipod touch version is encoded with audio in AAC, not mp3. Low motion
scenes look better.

I would rather transcode down to 200 kbit rather than 0 kbit (delete the
file).

This is actually from an ipod video conversion script. Quite frankly, I
think the quality could be slightly better yet so thats why I am still
refining the script. I'm hoping to get 2 pass encoding to work. However I
think 2 pass x264 in ffmpeg is broken. The pass log file gets created but
it is zero length. I might eventually settle with 250 or 300 kbit. And I
think I will try mencoder as well. My mencoder doesn't have h264 support
though, so I would have to recompile.

I'm currently watching a transcoded episode and noticed that even with
commercial skip off, the video would skip commercials. I guess this is
probably the intended behavior when you do a mythcommflag gencutlist. I
will probably remove that from the script.

So, the issue remaining is really just the video distortion with each seek
which lasts a few seconds.

If anyone has any "formulas" for x264 encoding, please share.

Thanks
Chris

cmisipster at gmail

Feb 19, 2008, 4:42 AM

Post #9 of 36 (5058 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

As a further script refinement, I am thinking of setting the Group name of
my h264 encoded videos to be different from anything else.

I just thought about something. Since the video is at 200 kbits, doesn't
that make placeshifting possible? (Slingbox without a slingbox). Or are
there other technical hurdles to having a mythfrontend running outside of
your lan, and connecting to your home server.

My upload speed is 470 kbps so I think it might work.

Any ideas?

drayson at net1plus

Feb 19, 2008, 4:49 AM

Post #10 of 36 (5056 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

I cannot get this script to work. There must be a line feed somewhere in my
copy that shouldn't be.

Chris, can you email it to me as an attachment?

Marc

From: mythtv-users-bounces [at] mythtv
[mailto:mythtv-users-bounces [at] mythtv] On Behalf Of Chris Isip
Sent: Monday, February 18, 2008 9:30 PM
To: Discussion about mythtv
Subject: [mythtv-users] Encoding to h264 to save space

I am able to shrink 1 hour of video to approximately 150 MB at 200 kbit with
ffmpeg using h264. Seems to work well except with seeking. I wonder if
this is a keyframe issue. When I forward or rewind, there is distortion for
a few seconds and then the video fixes itself. If I forward or rewind
before the video is fixed, the progress bar seems to jump back. Seeking is
more reliable when the distrotion is allowed to clear first. Also, I cannot
jump to the very first frame of the recording. If I exit the recording and
play it again, I start on the first frame. Here is a copy of my latest
script. Single pass for now (hoping to go to 2 pass). I was wondering if
anyone could give me any ideas as to how to fix this issue.

Thanks
Chris

#!/bin/bash
VIDEO_DIR=/mnt/VIDEO

#subq to 7 trellis to 2 threads 2
#need to clear the cutlist and generate it again

function convert-to-h264 ()
{
#argument is file only (no path)
#need to dereference a symlink
inputfile=`ls -ld $VIDEO_DIR/$1 | awk -F" " '{ print $NF }'`

echo "Will encode $inputfile"
basedname=`echo $inputfile | sed 's,^$.*/$\?$[^/]*$,\2,'`
vidformat=`mplayer -vo null -ao null -frames 0 -identify "$inputfile"
2>/dev/null | grep "ID_VIDEO_FORMAT" | sed -e 's/ID_VIDEO_FORMAT=//'`

if ! [ "$vidformat" == "H264" ]; then
/usr/bin/ffmpeg -threads 2 -i $inputfile -acodec mp3 -ac 2 -ar 44100 -ab
128k -s 320x240 -vcodec h264 -sameq -flags +loop -cmp +chroma -partitions
+parti4x4+partp8x8+partb8x8 -me umh -subq 7 -trellis 2 -refs 1 -coder 0
-me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 300k
-maxrate 300k -bufsize 300k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 15
-qmax 51 -qdiff 4 -level 30 -aspect 320:240 $inputfile.avi

mv $inputfile $inputfile.old
mv $inputfile.avi $inputfile

echo "Building seek table"
mythcommflag --rebuild -f "$inputfile"

echo "Clearing the cut list"
mythcommflag --clearcutlist -f $inputfile

echo "Commercial skip to cutlist"
mythcommflag --gencutlist -f $inputfile

filesize=$(wc -c $inputfile | awk '{print $1}')
echo "Updating database"
mysql -umythtv -pmythtv -hmymythtv mythconverg -se"UPDATE recorded SET
cutlist=0,filesize=$filesize WHERE basename=\"$basedname\";"
else
echo "Already an H264"

fi
}

CONVLIST=`mysql -umythtv -pmythtv -hmymythtv mythconverg -se"select basename
from recorded where title like \"%$1%\";"`

for i in ${CONVLIST[@]} ; do
if ! test -L $VIDEO_DIR/$i ; then #its not a symnlink
#Check if this recording is done -mmin +5
filetoconvert=`find $VIDEO_DIR -name $i -mmin +5 | sed
's,^$.*/$\?$[^/]*$,\2,'`
if [ -z "$filetoconvert" ]; then
echo "$i is not finnished recording...Skipping"
else
echo "Moving $i to /mnt/VIDEO1"
mv $VIDEO_DIR/$i /mnt/VIDEO1
ln -sf /mnt/VIDEO1/$i $VIDEO_DIR/$i
convert-to-h264 $i
fi
else
echo "$i is already a symlink...Skipping"
convert-to-h264 $i
fi

done
[root [at] mygamep cmisip]# cat /usr/local/bin/RECconv2.sh
#!/bin/bash
VIDEO_DIR=/mnt/VIDEO

#subq to 7 trellis to 2 threads 2
#need to clear the cutlist and generate it again

function convert-to-h264 ()
{
#argument is file only (no path)
#need to dereference a symlink
inputfile=`ls -ld $VIDEO_DIR/$1 | awk -F" " '{ print $NF }'`

echo "Will encode $inputfile"
basedname=`echo $inputfile | sed 's,^$.*/$\?$[^/]*$,\2,'`
vidformat=`mplayer -vo null -ao null -frames 0 -identify "$inputfile"
2>/dev/null | grep "ID_VIDEO_FORMAT" | sed -e 's/ID_VIDEO_FORMAT=//'`

if ! [ "$vidformat" == "H264" ]; then
/usr/bin/ffmpeg -threads 2 -i $inputfile -acodec mp3 -ac 2 -ar 44100 -ab
128k -s 320x240 -vcodec h264 -sameq -flags +loop -cmp +chroma -partitions
+parti4x4+partp8x8+partb8x8 -me umh -subq 7 -trellis 2 -refs 1 -coder 0
-me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 300k
-maxrate 300k -bufsize 300k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 15
-qmax 51 -qdiff 4 -level 30 -aspect 320:240 $inputfile.avi

mv $inputfile $inputfile.old
mv $inputfile.avi $inputfile

echo "Building seek table"
mythcommflag --rebuild -f "$inputfile"

echo "Clearing the cut list"
mythcommflag --clearcutlist -f $inputfile

echo "Commercial skip to cutlist"
mythcommflag --gencutlist -f $inputfile

filesize=$(wc -c $inputfile | awk '{print $1}')
echo "Updating database"
mysql -umythtv -pmythtv -hmymythtv mythconverg -se"UPDATE recorded SET
cutlist=0,filesize=$filesize WHERE basename=\"$basedname\";"
else
echo "Already an H264"

fi
}

CONVLIST=`mysql -umythtv -pmythtv -hmymythtv mythconverg -se"select basename
from recorded where title like \"%$1%\";"`

for i in ${CONVLIST[@]} ; do
if ! test -L $VIDEO_DIR/$i ; then #its not a symnlink
#Check if this recording is done -mmin +5
filetoconvert=`find $VIDEO_DIR -name $i -mmin +5 | sed
's,^$.*/$\?$[^/]*$,\2,'`
if [ -z "$filetoconvert" ]; then
echo "$i is not finnished recording...Skipping"
else
echo "Moving $i to /mnt/VIDEO1"
mv $VIDEO_DIR/$i /mnt/VIDEO1
ln -sf /mnt/VIDEO1/$i $VIDEO_DIR/$i
convert-to-h264 $i
fi
else
echo "$i is already a symlink...Skipping"
convert-to-h264 $i
fi

done

jedi at mishnet

Feb 19, 2008, 8:04 AM

Post #11 of 36 (5058 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

My original backend was an underperforming ATI based system.
It had precisely this problem. This issue went away once I
replaced it with a mac mini. Check the load on your system
and see if you aren't maxing it out. Your box might not have
enough muscle to seek through h264 in realtime.

I also have another nv 6100 based system with a similar cpu
to the old ATI underperformer. This system can also seek fine
through h264 files.

Although I have never compressed as agressively as you do.

I don't know if that could be an issue.

> I cannot get this script to work. There must be a line feed somewhere in
> my
> copy that shouldn't be.
>
> Chris, can you email it to me as an attachment?
>
>
>
> Marc
>
>
>
> From: mythtv-users-bounces [at] mythtv
> [mailto:mythtv-users-bounces [at] mythtv] On Behalf Of Chris Isip
> Sent: Monday, February 18, 2008 9:30 PM
> To: Discussion about mythtv
> Subject: [mythtv-users] Encoding to h264 to save space
>
>
>
> I am able to shrink 1 hour of video to approximately 150 MB at 200 kbit
> with
> ffmpeg using h264. Seems to work well except with seeking. I wonder if
> this is a keyframe issue. When I forward or rewind, there is distortion
> for
> a few seconds and then the video fixes itself. If I forward or rewind
> before the video is fixed, the progress bar seems to jump back. Seeking
> is
> more reliable when the distrotion is allowed to clear first. Also, I
> cannot
> jump to the very first frame of the recording. If I exit the recording
> and
> play it again, I start on the first frame. Here is a copy of my latest
> script. Single pass for now (hoping to go to 2 pass). I was wondering if
> anyone could give me any ideas as to how to fix this issue.
>
> Thanks
> Chris
>
>
> #!/bin/bash
> VIDEO_DIR=/mnt/VIDEO
>
> #subq to 7 trellis to 2 threads 2
> #need to clear the cutlist and generate it again
>
>
>
>
> function convert-to-h264 ()
> {
> #argument is file only (no path)
> #need to dereference a symlink
> inputfile=`ls -ld $VIDEO_DIR/$1 | awk -F" " '{ print $NF }'`
>
> echo "Will encode $inputfile"
> basedname=`echo $inputfile | sed 's,^$.*/$\?$[^/]*$,\2,'`
> vidformat=`mplayer -vo null -ao null -frames 0 -identify "$inputfile"
> 2>/dev/null | grep "ID_VIDEO_FORMAT" | sed -e 's/ID_VIDEO_FORMAT=//'`
>
>
>
> if ! [ "$vidformat" == "H264" ]; then
> /usr/bin/ffmpeg -threads 2 -i $inputfile -acodec mp3 -ac 2 -ar 44100 -ab
> 128k -s 320x240 -vcodec h264 -sameq -flags +loop -cmp +chroma -partitions
> +parti4x4+partp8x8+partb8x8 -me umh -subq 7 -trellis 2 -refs 1 -coder 0
> -me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt
> 300k
> -maxrate 300k -bufsize 300k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin
> 15
> -qmax 51 -qdiff 4 -level 30 -aspect 320:240 $inputfile.avi
>
>
> mv $inputfile $inputfile.old
> mv $inputfile.avi $inputfile
>
>
> echo "Building seek table"
> mythcommflag --rebuild -f "$inputfile"
>
> echo "Clearing the cut list"
> mythcommflag --clearcutlist -f $inputfile
>
> echo "Commercial skip to cutlist"
> mythcommflag --gencutlist -f $inputfile
>
> filesize=$(wc -c $inputfile | awk '{print $1}')
> echo "Updating database"
> mysql -umythtv -pmythtv -hmymythtv mythconverg -se"UPDATE recorded SET
> cutlist=0,filesize=$filesize WHERE basename=\"$basedname\";"
> else
> echo "Already an H264"
>
> fi
> }
>
>
> CONVLIST=`mysql -umythtv -pmythtv -hmymythtv mythconverg -se"select
> basename
> from recorded where title like \"%$1%\";"`
>
> for i in ${CONVLIST[@]} ; do
> if ! test -L $VIDEO_DIR/$i ; then #its not a symnlink
> #Check if this recording is done -mmin +5
> filetoconvert=`find $VIDEO_DIR -name $i -mmin +5 | sed
> 's,^$.*/$\?$[^/]*$,\2,'`
> if [ -z "$filetoconvert" ]; then
> echo "$i is not finnished recording...Skipping"
> else
> echo "Moving $i to /mnt/VIDEO1"
> mv $VIDEO_DIR/$i /mnt/VIDEO1
> ln -sf /mnt/VIDEO1/$i $VIDEO_DIR/$i
> convert-to-h264 $i
> fi
> else
> echo "$i is already a symlink...Skipping"
> convert-to-h264 $i
> fi
>
>
>
>
> done
> [root [at] mygamep cmisip]# cat /usr/local/bin/RECconv2.sh
> #!/bin/bash
> VIDEO_DIR=/mnt/VIDEO
>
> #subq to 7 trellis to 2 threads 2
> #need to clear the cutlist and generate it again
>
>
>
>
> function convert-to-h264 ()
> {
> #argument is file only (no path)
> #need to dereference a symlink
> inputfile=`ls -ld $VIDEO_DIR/$1 | awk -F" " '{ print $NF }'`
>
> echo "Will encode $inputfile"
> basedname=`echo $inputfile | sed 's,^$.*/$\?$[^/]*$,\2,'`
> vidformat=`mplayer -vo null -ao null -frames 0 -identify "$inputfile"
> 2>/dev/null | grep "ID_VIDEO_FORMAT" | sed -e 's/ID_VIDEO_FORMAT=//'`
>
>
>
> if ! [ "$vidformat" == "H264" ]; then
> /usr/bin/ffmpeg -threads 2 -i $inputfile -acodec mp3 -ac 2 -ar 44100 -ab
> 128k -s 320x240 -vcodec h264 -sameq -flags +loop -cmp +chroma -partitions
> +parti4x4+partp8x8+partb8x8 -me umh -subq 7 -trellis 2 -refs 1 -coder 0
> -me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt
> 300k
> -maxrate 300k -bufsize 300k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin
> 15
> -qmax 51 -qdiff 4 -level 30 -aspect 320:240 $inputfile.avi
>
>
> mv $inputfile $inputfile.old
> mv $inputfile.avi $inputfile
>
>
> echo "Building seek table"
> mythcommflag --rebuild -f "$inputfile"
>
> echo "Clearing the cut list"
> mythcommflag --clearcutlist -f $inputfile
>
> echo "Commercial skip to cutlist"
> mythcommflag --gencutlist -f $inputfile
>
> filesize=$(wc -c $inputfile | awk '{print $1}')
> echo "Updating database"
> mysql -umythtv -pmythtv -hmymythtv mythconverg -se"UPDATE recorded SET
> cutlist=0,filesize=$filesize WHERE basename=\"$basedname\";"
> else
> echo "Already an H264"
>
> fi
> }
>
>
> CONVLIST=`mysql -umythtv -pmythtv -hmymythtv mythconverg -se"select
> basename
> from recorded where title like \"%$1%\";"`
>
> for i in ${CONVLIST[@]} ; do
> if ! test -L $VIDEO_DIR/$i ; then #its not a symnlink
> #Check if this recording is done -mmin +5
> filetoconvert=`find $VIDEO_DIR -name $i -mmin +5 | sed
> 's,^$.*/$\?$[^/]*$,\2,'`
> if [ -z "$filetoconvert" ]; then
> echo "$i is not finnished recording...Skipping"
> else
> echo "Moving $i to /mnt/VIDEO1"
> mv $VIDEO_DIR/$i /mnt/VIDEO1
> ln -sf /mnt/VIDEO1/$i $VIDEO_DIR/$i
> convert-to-h264 $i
> fi
> else
> echo "$i is already a symlink...Skipping"
> convert-to-h264 $i
> fi
>
>
>
>
> done
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

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cmisipster at gmail

Feb 19, 2008, 3:11 PM

Post #12 of 36 (5036 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 19, 2008 11:04 AM, <jedi [at] mishnet> wrote:

> My original backend was an underperforming ATI based system.
> It had precisely this problem. This issue went away once I
> replaced it with a mac mini. Check the load on your system
> and see if you aren't maxing it out. Your box might not have
> enough muscle to seek through h264 in realtime.
>
> I also have another nv 6100 based system with a similar cpu
> to the old ATI underperformer. This system can also seek fine
> through h264 files.
>
> Although I have never compressed as agressively as you do.
>
> I don't know if that could be an issue.
>

I have a new Dell Vostro 200 with a dual core 2.2 Ghz cpu. I checked the
cpu usage and it stays at about 10 % while playing back the file in mythtv
and seeking. So it has to be something else. I also played the h264 video
with mplayer and I didn't see any graphic distortion with seeking. This
seems to be a mythtv issue only.

Thanks
Chris

jedi at mishnet

Feb 19, 2008, 3:18 PM

Post #13 of 36 (5039 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

> On Feb 19, 2008 11:04 AM, <jedi [at] mishnet> wrote:
>
>> My original backend was an underperforming ATI based system.
>> It had precisely this problem. This issue went away once I
>> replaced it with a mac mini. Check the load on your system
>> and see if you aren't maxing it out. Your box might not have
>> enough muscle to seek through h264 in realtime.
>>
>> I also have another nv 6100 based system with a similar cpu
>> to the old ATI underperformer. This system can also seek fine
>> through h264 files.
>>
>> Although I have never compressed as agressively as you do.
>>
>> I don't know if that could be an issue.
>>
>
> I have a new Dell Vostro 200 with a dual core 2.2 Ghz cpu. I checked
> the
> cpu usage and it stays at about 10 % while playing back the file in mythtv
> and seeking. So it has to be something else. I also played the h264
> video
> with mplayer and I didn't see any graphic distortion with seeking. This
> seems to be a mythtv issue only.

Possible. I have had my own problems with the internal player and h264.

This is one of the reasons I use xine as my external player in mythvideo.

[deletia]

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taco_mel at yahoo

Feb 19, 2008, 10:50 PM

Post #14 of 36 (5019 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

> Seems to work well except with seeking. I wonder if
> this is a keyframe issue. When I forward or rewind,
> there is distortion for a few seconds and then the
> video fixes itself...

Yes this is probably a keyframe issue. If you hit the
video between the keyframes you will see distortion
until you hit the next keyframe, and then it will
clear up.

I have been transcoding to H.264 for a couple weeks
now after going through all sorts of pain, mostly
along the lines of "it works in mplayer but not in
MythTV." Here is what I found:

1) In my experience, it works better if you completely
whack (do not rebuild) the seek table. So instead of
mythcommflag --rebuild, I am issuing SQL deleting from
the recordedseek table where channel ID and start time
match the recording I just transcoded. From my
reading of the code, absent the seek table, it will
fall back and figure it out on its own. Works for me,
except:

2) On some recordings, generally greater than 1 hour
30 minutes, I am unable to seek to the beginning.
Usually when you hit "UP" with under 10 minutes
played, it will start at the beginning. But in
certain recordings this does nothing. I have not
tried to troubleshoot further.

I tried this first with rebuilding the seek table
using mythcommflag, and there were always one of three
results. Either mythcommflag segfaulted before
updating the table, or even after rebuilding the table
I would get the "keyframe distortion" issue, or MythTV
would refuse to play the file (sometimes segfaulting,
sometimes hanging for several seconds and then
returning to the preview). I tried lots of things,
including using mencoder to ensure that the first
frame of the file was a keyframe, and even making
every frame a keyframe, to no avail. So for now I am
clearing out the seek table and it works flawlessly on
95% of my recordings and acceptably on the other 5%.

Also, I have set the keyframe interval to 15. I have
seen suggestions or defaults in the 300 range, which
is 1 keyframe every 10 seconds at 30 fps. Setting it
to 15 allows you to seek to the nearest 1/2 second
which should be fine.

Finally, I am using mencoder and not ffmpeg. This is
mainly because I found more examples with mencoder
back when I had no idea what I was doing. It does
have a very nice option to put the settings into a
file and then call it with "mencoder
--profile=WHATEVER ..." and not have to
remember/retype the settings every time. I now have
profiles optimized for different types of shows (e.g.,
anime, sports, etc.) with different bitrates and
options.

I am compressing down to about 400 MB per half hour.
I have a 65 inch TV and anything lower than that
displays obvious distortion.

If you decide to go with the mencoder route, I suggest
that you check out 'h264enc'
(http://h264enc.sourceforge.net/). It interactively
guides you through a bunch of options. When you get
done it asks you, do you want to see the options, and
do you want to save the options to a file. That's a
great starting point for you to go through and figure
out what everything means.

I plan, after further refinement, to offer up my Myth
optimized h264 transcoding script as a contribution,
or sourceforge project, or whatever. I've still got
to update it to use the MythTV perl bindings and get
some feedback about the "whack the seek table"
approach before I offer it up. If you want to try it
out shoot me an e-mail and I'll send it along.

____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
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philledwards at gmail

Feb 20, 2008, 1:56 AM

Post #15 of 36 (5006 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

How are people watching these transcoded recordings? Are you using
MythVideo or do they somehow appear under Watch Recordings (if so,
how)?

Also, one of the posters mentioned they were getting down to 400MB per
30 mins. Using the in-built transcoder (Autodetect from MPEG2 -->
MPEG4) I'm getting approx 550MB per 30 minutes, so it doesn't sound
like an enormous saving to go to all this trouble to get h264 - are
there other benefits of this aside from the space savings?

My transcode settings are:
Bitrate = 2500
Max Quality = 2
Min Quality = 15
Scale bitrate for frame size = off
Max quality diff between frames = 3
Enable high quality encoding = on
Enable interlaced DCT encoding = off
Enable 4MV encoding = on
Enable interlaced motion estimation = off

Regards,
Phill
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cmisipster at gmail

Feb 20, 2008, 3:00 AM

Post #16 of 36 (5010 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 20, 2008 4:56 AM, Phill Edwards <philledwards [at] gmail> wrote:

> How are people watching these transcoded recordings? Are you using
> MythVideo or do they somehow appear under Watch Recordings (if so,
> how)?
>
> Also, one of the posters mentioned they were getting down to 400MB per
> 30 mins. Using the in-built transcoder (Autodetect from MPEG2 -->
> MPEG4) I'm getting approx 550MB per 30 minutes, so it doesn't sound
> like an enormous saving to go to all this trouble to get h264 - are
> there other benefits of this aside from the space savings?
>
> My transcode settings are:
> Bitrate = 2500
> Max Quality = 2
> Min Quality = 15
> Scale bitrate for frame size = off
> Max quality diff between frames = 3
> Enable high quality encoding = on
> Enable interlaced DCT encoding = off
> Enable 4MV encoding = on
> Enable interlaced motion estimation = off
>
> Regards,
> Phill
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

I am watching them in Watch Recordings, not MythVideo, hence using the
internal player. The script renames the reencoded file to match the
original file and the original file is renamed with a .old extension in case
you want to revert. A final database update updates filesize and cutlist
status in mythconverg. I have added some other refinements since I posted
this including: excluding LiveTV recordings, setting the recgroup of
reencoded videos to "Archive", removing the line that imports the
commercial skip into the cutlist.

gull at gull

Feb 20, 2008, 2:21 PM

Post #17 of 36 (4987 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 20, 2008, at 1:56 AM, Phill Edwards wrote:
> Also, one of the posters mentioned they were getting down to 400MB per
> 30 mins. Using the in-built transcoder (Autodetect from MPEG2 -->
> MPEG4) I'm getting approx 550MB per 30 minutes, so it doesn't sound
> like an enormous saving to go to all this trouble to get h264 - are
> there other benefits of this aside from the space savings?

For stuff I really care about I like to use an external two-pass
transcoder. I feel the quality is a little better than using the
built-in one-pass transcoder, but at the cost of less convenience.

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cmisipster at gmail

Feb 21, 2008, 4:07 AM

Post #18 of 36 (4967 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Wed, Feb 20, 2008 at 5:21 PM, David Brodbeck <gull [at] gull> wrote:

>
> On Feb 20, 2008, at 1:56 AM, Phill Edwards wrote:
> > Also, one of the posters mentioned they were getting down to 400MB per
> > 30 mins. Using the in-built transcoder (Autodetect from MPEG2 -->
> > MPEG4) I'm getting approx 550MB per 30 minutes, so it doesn't sound
> > like an enormous saving to go to all this trouble to get h264 - are
> > there other benefits of this aside from the space savings?
>
> For stuff I really care about I like to use an external two-pass
> transcoder. I feel the quality is a little better than using the
> built-in one-pass transcoder, but at the cost of less convenience.
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

I have found out a few things: mythcommflag will not work if you are not in
the current directory of the recordings when you run the script; "Seek to
exact frame" helps the distortion issue but does not completely eliminate
it.

Also, I have been trying to setup my dual core machine to do this, but
ffmpeg segfaults. It is a Centos 5.1 machine. It works fine on my
hyperthreaded cpu machine. Is anyone able to use the latest ffmpeg to
encode to h264? What ffmpeg versions are you guys using for h264?

I tried to compile the version from my FC5 machine to run on the centos
machine and it gives me monotone errors when I run it
ffmpeg-0.4.9-23_r8743.fc5in Centos. Works fine in FC5.

This version works in FC5 :
ffmpeg-0.4.9-23_r8743.fc5

Thanks
Chris

chrisribe at gmail

Feb 21, 2008, 11:14 AM

Post #19 of 36 (4959 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

>
> Also, I have been trying to setup my dual core machine to do this, but
> ffmpeg segfaults. It is a Centos 5.1 machine. It works fine on my
> hyperthreaded cpu machine. Is anyone able to use the latest ffmpeg to
> encode to h264? What ffmpeg versions are you guys using for h264?
>

Well, it's not the latest now, but it was 12 days ago. I use ffmpeg
SVN-r11556 to encode h264.

-chris

--
TV/IT Engineer
WCJB-TV Gainesville, FL
(352) 416 0648
cribe [at] wcjb

r-mythtv at thefreemanclan

Feb 21, 2008, 7:22 PM

Post #20 of 36 (4941 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

Taco Mel wrote:
> Yes this is probably a keyframe issue. If you hit the
> video between the keyframes you will see distortion
> until you hit the next keyframe, and then it will
> clear up.
>

I didn't see this posted yet, so I'll point it out. Unless something
has changed mythtv's internal player does not support non-uniform
keyframes. If there isn't a keyframe exactly every 15/18 frames or so
(with a constant interval) the seektable doesn't work.

The problem is that instead of storing frame numbers the seektable
stores the keyframe number and the player just multiples it by 15/18 to
get the frame number.

It seems like 80% of my transcoding frustrations are the result of the
internal player. I really appreciate the great system that mythtv is,
but I'm not quite sure why they decided to write their own
players/transcoders/etc instead of using mplayer/xine-lib/whatever.
Video that plays just fine in mplayer/xine doesn't work at all in
mythtv. So I just use mythvideo if I have to play it and lose the
ability to bookmark, commercial-skip, etc.

I've been trying for over a year now to transcode HD video to SD while
keeping the AC3 soundtrack in place. I've yet to find a set of settings
that works reliably with seeking. Just about anything I try works fine
in mplayer though. I don't have a frontend capable of playing HD but I
am interested in capturing it anyway just so that I can get the AC3
surround tracks...

Oh well... Maybe somebody will fix it eventually. I can't complain too
much - I don't have the time to write a whole new player for myth, and
it is worth a TON more than I paid for it! :)

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cpinkham at bc2va

Feb 21, 2008, 7:34 PM

Post #21 of 36 (4935 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

* On Thu Feb 21, 2008 at 10:22:57PM -0500, Richard Freeman wrote:
> It seems like 80% of my transcoding frustrations are the result of the
> internal player. I really appreciate the great system that mythtv is,
> but I'm not quite sure why they decided to write their own
> players/transcoders/etc instead of using mplayer/xine-lib/whatever.

Because our versions work the way we want and aren't subject to outside
changes.

> Video that plays just fine in mplayer/xine doesn't work at all in
> mythtv. So I just use mythvideo if I have to play it and lose the
> ability to bookmark, commercial-skip, etc.

I think you just answered your own question. With those external apps,
you'd lose all the features that our internal player supports.

> I've been trying for over a year now to transcode HD video to SD while
> keeping the AC3 soundtrack in place. I've yet to find a set of settings
> that works reliably with seeking. Just about anything I try works fine
> in mplayer though. I don't have a frontend capable of playing HD but I
> am interested in capturing it anyway just so that I can get the AC3
> surround tracks...

I've successfully tested a hack to do just what you're looking for,
I transcoded from mpeg-ps containing MPEG-2 video and AC3 audio down to
a .nuv file containing MPEG-4 video and the original AC3 audio. This was
a hack test on top of another large modification I'm working on to modify
the software recorder to support multiple file formats and additional
codecs. Don't expect this in SVN anytime soon, but it it something
that's on my TODO. I much prefer the original AC3 audio to reencoded MP3
in the files that I do transcode.

--
Chris
_______________________________________________
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drayson at net1plus

Feb 21, 2008, 8:53 PM

Post #22 of 36 (4940 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

* On Thu Feb 21, 2008 at 10:22:57PM -0500, Richard Freeman wrote:
> It seems like 80% of my transcoding frustrations are the result of the
> internal player. I really appreciate the great system that mythtv is,
> but I'm not quite sure why they decided to write their own
> players/transcoders/etc instead of using mplayer/xine-lib/whatever.

Because our versions work the way we want and aren't subject to outside
changes.

> Video that plays just fine in mplayer/xine doesn't work at all in
> mythtv. So I just use mythvideo if I have to play it and lose the
> ability to bookmark, commercial-skip, etc.

I think you just answered your own question. With those external apps,
you'd lose all the features that our internal player supports.

> I've been trying for over a year now to transcode HD video to SD while
> keeping the AC3 soundtrack in place. I've yet to find a set of settings
> that works reliably with seeking. Just about anything I try works fine
> in mplayer though. I don't have a frontend capable of playing HD but I
> am interested in capturing it anyway just so that I can get the AC3
> surround tracks...

I've successfully tested a hack to do just what you're looking for,
I transcoded from mpeg-ps containing MPEG-2 video and AC3 audio down to
a .nuv file containing MPEG-4 video and the original AC3 audio. This was
a hack test on top of another large modification I'm working on to modify
the software recorder to support multiple file formats and additional
codecs. Don't expect this in SVN anytime soon, but it it something
that's on my TODO. I much prefer the original AC3 audio to reencoded MP3
in the files that I do transcode.

--
Chris
_______________________________________________

Something I noticed recently with my own attempts to reencode to h264. I
changed the "-acodec mp3" to "-acodec copy" in my modified script for ffmpeg
because I wanted to keep the ac3 surround in my converted files. Apparently
the copy function is broken in ffmpeg and I have found several other people
commenting on this same issue.

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cmisipster at gmail

Feb 22, 2008, 3:17 AM

Post #23 of 36 (4925 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

So, do I need to set keyint to 15 or 18 to improve the seeking issue? I
assume this is what it would need to set keyframes every 15 or 18. I will
try this and the suggestion earlier to not rebuild the seektable at all.

I noticed that if I try to encode a live tv clip, I get horrible audio video
sync. Is there anything different in how live tv and scheduled recordings
are encoded by myth? A-V sync is perfect with reencoded scheduled
recordings.

Thanks

Chris

gull at gull

Feb 22, 2008, 9:21 AM

Post #24 of 36 (4917 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

On Feb 22, 2008, at 3:17 AM, Chris Isip wrote:
> I noticed that if I try to encode a live tv clip, I get horrible
> audio video sync. Is there anything different in how live tv and
> scheduled recordings are encoded by myth?

There might be, depending on how you set up your system. LiveTV has
its own recording profile.

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r-mythtv at thefreemanclan

Feb 22, 2008, 12:22 PM

Post #25 of 36 (4909 views)
Permalink

Re: Encoding to h264 to save space [In reply to]

Chris Pinkham wrote:
> * On Thu Feb 21, 2008 at 10:22:57PM -0500, Richard Freeman wrote:
>> Video that plays just fine in mplayer/xine doesn't work at all in
>> mythtv. So I just use mythvideo if I have to play it and lose the
>> ability to bookmark, commercial-skip, etc.
>
> I think you just answered your own question. With those external apps,
> you'd lose all the features that our internal player supports.
>

True enough. Although it would be nice if you could tap into those
libraries and yet maintain control of the seeking. If you could just
get mplayer or xine-lib to skip to frame xyz on demand that would
probably do the trick. But you are correct that you do limit yourself
to some degree in this way - especially with stuff like
picture-in-picture, OSD, etc. Maybe the library providers would
entertain accepting patches to get them to behave the way you want, and
you could always fork in the worst case.

>
> I've successfully tested a hack to do just what you're looking for,
> I transcoded from mpeg-ps containing MPEG-2 video and AC3 audio down to
> a .nuv file containing MPEG-4 video and the original AC3 audio. This was
> a hack test on top of another large modification I'm working on to modify
> the software recorder to support multiple file formats and additional
> codecs. Don't expect this in SVN anytime soon, but it it something
> that's on my TODO. I much prefer the original AC3 audio to reencoded MP3
> in the files that I do transcode.
>

That's GREAT to hear! A transcoding option to preserve AC3 while
downsizing the video to H264 (or MPEG2 if you must) would be wonderful!

Again, I don't want to knock the great system that myth is. Especially
when the most I've contributed is a little patch to add an icon for
preserved programs to the program listing...
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