Mailing List Archive: MythTV: Users

Cropping NTSC to 16:9

Index | Next | Previous | View Threaded

chmeredith at gmail

Feb 13, 2009, 11:01 AM

Post #1 of 6 (979 views)
Permalink

Cropping NTSC to 16:9

I use an SA3250HD cable box. I get my analog channels via s-video and
my HD channels via firewire. My premium HD channels are 5c encrypted
so I can't grab them over firewire. They all have standard definition
equivalents on my channel lineup, but as I have a 16:9 TV, I'd like to
keep the 16:9 aspect ratio even if I can't keep the HD resolution.
When tuned to the HD channels, the cable box "letterboxes" the feed
before outputting to s-video. I would like to see if I can create a
video source or at least set custom "per channel" options that will
crop out the top/bottom black bars and display the video in 16:9
resolution. There are a couple things I've tried:

MANUAL ZOOM
Obviously, if I am watching such a channel and I set the manual zoom
to "full," it displays exactly as I have in mind. The problem is this
is not an automatic solution and I can't figure out a way to set the
default zoom method on a per-channel basis. Is this possible?

CROPPING
The other method I tried is using a video filter to crop the black
bars out. The problem appears to be that the "crop" filter in MythTV
doesn't work the same way as the crop filter in, say, mplayer. It
appears that when using an NTSC capture card, the recorded video will
always be 720x480 and the crop settings are meant to be used with
equal values all around. If I set the record filter to "crop=4:0:4:0",
it does crop out the unwanted bars, but the recorded video is still
720x480 and the "dead space" is filled with distorted patterns. The
same is true if I use the same string in the playback filter field.

Can anyone recommend a method to "un-letterbox" an NTSC feed and
automatically display a 16:9 resolution?

Thanks!

Christopher
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

nick.rout at gmail

Feb 13, 2009, 2:31 PM

Post #2 of 6 (925 views)
Permalink

Re: Cropping NTSC to 16:9 [In reply to]

On Sat, Feb 14, 2009 at 8:01 AM, Christopher Meredith
<chmeredith [at] gmail> wrote:
> I use an SA3250HD cable box. I get my analog channels via s-video and
> my HD channels via firewire. My premium HD channels are 5c encrypted
> so I can't grab them over firewire. They all have standard definition
> equivalents on my channel lineup, but as I have a 16:9 TV, I'd like to
> keep the 16:9 aspect ratio even if I can't keep the HD resolution.
> When tuned to the HD channels, the cable box "letterboxes" the feed
> before outputting to s-video. I would like to see if I can create a
> video source or at least set custom "per channel" options that will
> crop out the top/bottom black bars and display the video in 16:9
> resolution. There are a couple things I've tried:
>
> MANUAL ZOOM
> Obviously, if I am watching such a channel and I set the manual zoom
> to "full," it displays exactly as I have in mind. The problem is this
> is not an automatic solution and I can't figure out a way to set the
> default zoom method on a per-channel basis. Is this possible?
>
> CROPPING
> The other method I tried is using a video filter to crop the black
> bars out. The problem appears to be that the "crop" filter in MythTV
> doesn't work the same way as the crop filter in, say, mplayer. It
> appears that when using an NTSC capture card, the recorded video will
> always be 720x480 and the crop settings are meant to be used with
> equal values all around. If I set the record filter to "crop=4:0:4:0",
> it does crop out the unwanted bars, but the recorded video is still
> 720x480 and the "dead space" is filled with distorted patterns. The
> same is true if I use the same string in the playback filter field.
>
> Can anyone recommend a method to "un-letterbox" an NTSC feed and
> automatically display a 16:9 resolution?
>

is there a setting on the cable box to fix that?
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

junk_inbox at verizon

Feb 13, 2009, 5:21 PM

Post #3 of 6 (918 views)
Permalink

Re: Cropping NTSC to 16:9 [In reply to]

On Fri, Feb 13, 2009 at 2:01 PM, Christopher Meredith
<chmeredith [at] gmail>wrote:

> I use an SA3250HD cable box. I get my analog channels via s-video and
> my HD channels via firewire. My premium HD channels are 5c encrypted
> so I can't grab them over firewire. They all have standard definition
> equivalents on my channel lineup, but as I have a 16:9 TV, I'd like to
> keep the 16:9 aspect ratio even if I can't keep the HD resolution.
> When tuned to the HD channels, the cable box "letterboxes" the feed
> before outputting to s-video. I would like to see if I can create a
> video source or at least set custom "per channel" options that will
> crop out the top/bottom black bars and display the video in 16:9
> resolution. There are a couple things I've tried:
>
> MANUAL ZOOM
> Obviously, if I am watching such a channel and I set the manual zoom
> to "full," it displays exactly as I have in mind. The problem is this
> is not an automatic solution and I can't figure out a way to set the
> default zoom method on a per-channel basis. Is this possible?
>
> CROPPING
> The other method I tried is using a video filter to crop the black
> bars out. The problem appears to be that the "crop" filter in MythTV
> doesn't work the same way as the crop filter in, say, mplayer. It
> appears that when using an NTSC capture card, the recorded video will
> always be 720x480 and the crop settings are meant to be used with
> equal values all around. If I set the record filter to "crop=4:0:4:0",
> it does crop out the unwanted bars, but the recorded video is still
> 720x480 and the "dead space" is filled with distorted patterns. The
> same is true if I use the same string in the playback filter field.
>
> Can anyone recommend a method to "un-letterbox" an NTSC feed and
> automatically display a 16:9 resolution?
>
> Thanks!
>
> Christopher
>

Christopher,

Check if there's a way in the box to set it to 'anamorphic' output. That
will output the 16:9 video stretched in a 4:3 frame.

J-e-f-f-A

chmeredith at gmail

Feb 14, 2009, 8:22 PM

Post #4 of 6 (885 views)
Permalink

Re: Cropping NTSC to 16:9 [In reply to]

It looks like the SA3250HD does not have the ability to do anamorphic
output over s-video. Am I completely out of luck?

On Fri, Feb 13, 2009 at 7:21 PM, Jeff <junk_inbox [at] verizon> wrote:
>
>
> On Fri, Feb 13, 2009 at 2:01 PM, Christopher Meredith <chmeredith [at] gmail>
> wrote:
>>
>> I use an SA3250HD cable box. I get my analog channels via s-video and
>> my HD channels via firewire. My premium HD channels are 5c encrypted
>> so I can't grab them over firewire. They all have standard definition
>> equivalents on my channel lineup, but as I have a 16:9 TV, I'd like to
>> keep the 16:9 aspect ratio even if I can't keep the HD resolution.
>> When tuned to the HD channels, the cable box "letterboxes" the feed
>> before outputting to s-video. I would like to see if I can create a
>> video source or at least set custom "per channel" options that will
>> crop out the top/bottom black bars and display the video in 16:9
>> resolution. There are a couple things I've tried:
>>
>> MANUAL ZOOM
>> Obviously, if I am watching such a channel and I set the manual zoom
>> to "full," it displays exactly as I have in mind. The problem is this
>> is not an automatic solution and I can't figure out a way to set the
>> default zoom method on a per-channel basis. Is this possible?
>>
>> CROPPING
>> The other method I tried is using a video filter to crop the black
>> bars out. The problem appears to be that the "crop" filter in MythTV
>> doesn't work the same way as the crop filter in, say, mplayer. It
>> appears that when using an NTSC capture card, the recorded video will
>> always be 720x480 and the crop settings are meant to be used with
>> equal values all around. If I set the record filter to "crop=4:0:4:0",
>> it does crop out the unwanted bars, but the recorded video is still
>> 720x480 and the "dead space" is filled with distorted patterns. The
>> same is true if I use the same string in the playback filter field.
>>
>> Can anyone recommend a method to "un-letterbox" an NTSC feed and
>> automatically display a 16:9 resolution?
>>
>> Thanks!
>>
>> Christopher
>
> Christopher,
>
> Check if there's a way in the box to set it to 'anamorphic' output. That
> will output the 16:9 video stretched in a 4:3 frame.
>
> J-e-f-f-A
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

junk_inbox at verizon

Feb 14, 2009, 9:31 PM

Post #5 of 6 (885 views)
Permalink

Re: Cropping NTSC to 16:9 [In reply to]

On Sat, Feb 14, 2009 at 11:22 PM, Christopher Meredith <chmeredith [at] gmail
> wrote:

>
> > Check if there's a way in the box to set it to 'anamorphic' output.
> That
> > will output the 16:9 video stretched in a 4:3 frame.
> >
> > J-e-f-f-A
>
> It looks like the SA3250HD does not have the ability to do anamorphic
> output over s-video. Am I completely out of luck?
>
>
Check if it's got an aspect ratio setting for your TV - if so, set it to
16:9, it *should* have the same effect.

If it doesn't, you'll probably have to live with the black bars as long as
you're capturing the S-Video output.

J-e-f-f-A

chmeredith at gmail

Feb 15, 2009, 2:07 PM

Post #6 of 6 (865 views)
Permalink

Re: Cropping NTSC to 16:9 [In reply to]

No, the SA3250 doesn't have an option like that either.

So is it the case that the MythTV "crop" filter has no effect on the
dimensions of the recorded video? If this is the case, I don't see how
it would be useful for any purpose other than overscan. Can I somehow
interject mencoder as an intermediary step between capture and
display? Mencoder can crop out the black bars easily.

On Sat, Feb 14, 2009 at 11:31 PM, Jeff <junk_inbox [at] verizon> wrote:
> On Sat, Feb 14, 2009 at 11:22 PM, Christopher Meredith
> <chmeredith [at] gmail> wrote:
>>
>> > Check if there's a way in the box to set it to 'anamorphic' output.
>> > That
>> > will output the 16:9 video stretched in a 4:3 frame.
>> >
>> > J-e-f-f-A
>>
>> It looks like the SA3250HD does not have the ability to do anamorphic
>> output over s-video. Am I completely out of luck?
>>
>
> Check if it's got an aspect ratio setting for your TV - if so, set it to
> 16:9, it *should* have the same effect.
>
> If it doesn't, you'll probably have to live with the black bars as long as
> you're capturing the S-Video output.
>
> J-e-f-f-A
>
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

Index | Next | Previous | View Threaded

Interested in having your list archived? Contact Gossamer Threads