mythtv at hbuus
Feb 22, 2010, 9:47 AM
Post #2 of 2
Colin Law wrote:
Re: DVD authoring problem [was pvr-150 streaming question]
[In reply to]
> I have started a new thread as it has drifted rather off topic for the
> original post. With much help from the list, for which many thanks, I
> have used the method described in
> http://ivtvdriver.org/index.php/Howto:ivtv_for_dvdauthor to capture
> data from my pvr-150 and use a patched dvdauthor and mkisofs to
> generate a dvd iso image which I have burned to dvd. The dvd works
> fine in my PC but will not play in my dvd player, it says it is
> playing but nothing appears on screen.
> The only difference in settings that I have used from those specified
> in the above link are
> video_aspect=1 rather than 3
> audio_encoding=1 rather than audio_encoding_layer=1, I am guessing
> that the name for this changed at some point.
Are you in Europe or in North America? I think the author of the How To is in Europe (or the UK?) because he used this setting:
v4l2-ctl -s pal-I
But if you are in North America, you should use this:
v4l2-ctl -s ntsc
That could explain why your PC could play the DVD but your DVD player could not.
> One point that confuses me slightly is that recording of a little
> under two hours has generated an iso of only 2.5GB whereas I
> understood that a DVD of 4.7GB managed 2 hours of video. The captured
> mpg file is 2.4GB.
The file size is a function of the bit rates set with these commands:
v4l2-ctl -c video_bitrate=2750000
v4l2-ctl -c video_peak_bitrate=5000000
The video bitrate is the key. A video bitrate of 2,750,000 bits/sec (2.75 Mbps) will allow you to fit about 200 minutes on a 4.7 GB DVD. I like to use 2.05 Mbps because that lets me fit about 4 hours on a DVD. However, a higher bitrate should produce better quality. If you want better quality that will allow you to fit 2 hours on a DVD, try 4.7 Mbps or:
v4l2-ctl -c video_bitrate=4700000
You should probably increase the peak bitrate, too. In my experience, tinkering with the peak bitrate has little effect, but it does need to be greater than the video bitrate. DVD standards allow for a peak of over 9 Mbps. I would choose a value that's over 2 Mbps higher than the bitrate, or:
v4l2-ctl -c video_peak_bitrate=7000000
If I were you, I would do my testing with smaller clips of a few minutes and with rewritable DVD media (assuming your player can play rewritable media - read the manual) until I found what works.
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