[mythtv-users] UK DVB-T Channels 4, 5; multiple video streams

[John Pilkington]

On 05/06/13 11:03, John Pilkington wrote:
> On 04/06/13 19:46, John Pilkington wrote:
>> On 04/06/13 12:26, John Pilkington wrote:
>>> Last week the BBC mux from my local transmitter was moved to clear G4
>>> spectrum.  Since then my recordings from Channels 4 and 5 have
>>> apparently included multiple video streams.  This breaks my cutting
>>> script.  A simple edit ought to fix that, but has anything else changed
>>> too?
>>>
>>> $ ionice -c3 mythffmpeg -i  1005_20130603185800.mpg
>>> ffmpeg version 0.10.2.git Copyright (c) 2000-2012 the FFmpeg developers
>>>    built on Apr 27 2013 17:23:40 with gcc 4.7.2 20120921 (Red Hat
>>> 4.7.2-2)
>>
>> <snip>
>>
>>> Input #0, mpegts, from '1005_20130603185800.mpg':
>>>    Duration: 01:07:58.37, start: 51087.044133, bitrate: 2824 kb/s
>>>      Stream #0:0[0xb22]: Video: mpeg2video (Main), yuv420p, 704x576 [SAR
>>> 16:11 DAR 16:9], 15000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
>>>      Stream #0:1[0xb23](eng): Audio: mp2, 48000 Hz, stereo, s16, 192
>>> kb/s
>>>      Stream #0:2[0xb25](eng): Audio: mp2, 48000 Hz, mono, s16, 64 kb/s
>>>      Stream #0:3[0xb24](eng): Subtitle: dvb_subtitle
>>>      Stream #0:4[0x806]: Video: mpeg2video, 90k tbr, 90k tbn, 90k tbc
>>>      Stream #0:5[0x8cb]: Video: mpeg2video, 90k tbr, 90k tbn, 90k tbc
>>>      Stream #0:6[0x8cc]: Video: mpeg2video, 90k tbr, 90k tbn, 90k tbc
>>
>> mediainfo --version
>> MediaInfo Command line,
>> MediaInfoLib - v0.7.52
>>
>> mediainfo sees only the expected first four streams, with nothing
>> conspicuously wrong.  I guess mythffmpeg just picked a bad sampling
>> region, but I don't remember seeing results like this before.
>>
>
> I'm seeing the same results on my ScientificLinux6 laptop, and on
> Channel 3 (ITV), which is on the same mux as Channels 4 and 5.  It looks
> as if my script should now grep 'mpeg2video (Main)' instead of just
> 'Video' in the section aimed at selecting the video and audio PIDs.  The
> same change was needed a few months ago in MythArchive to allow DVD
> creation from DVB-T recordings without re-encoding.
>

I'm still seeing this, and this transmitter-specific page has several 
Media Center etc users who appear to be affected by it or something 
related to it.

http://www.ukfree.tv/txdetail.php?a=SK809233&PGSTART=1700#pagebar

I can think of no reason why this change, on the PSB2 mux,  should be 
linked to the retune of the PSB1 mux and I have no idea if the change 
affects other DVB-T transmitters.  It might help if people outside the 
East Midlands could run mythffmpeg -i <filename> on raw recordings from 
Channels 3,4,or 5.  Do you see multiple Video streams reported too?

Thanks,

John P