[mythtv] Mythtranscode HLS/AVF heavily distorted output

William Wilhelm will at wilhelm.com.au
Sun Jul 26 07:31:03 UTC 2015


I spent some time reverting commits affecting external/FFmpeg and got all 
the way back to FFmpeg 1.2.6, the version that works in 0.27. I have also 
reverted programs/mythtranscode back to 0.27 code. The distortion still 
happens.

Leads me to think it's not an FFmpeg issue.


On 25 July 2015 7:32:31 pm William Wilhelm <will at wilhelm.com.au> wrote:

> I have just tried this now, and the lossless transcode does strip the
> irrelevant streams, but the --avf transcode is still distorted.
>
>
> On 25 July 2015 7:11:43 pm John Pilkington <J.Pilk at tesco.net> wrote:
>
> > On 25/07/15 08:48, William Wilhelm wrote:
> > > Ever since 0.27 -> 0.28, mythtranscode --avf/--hls has been giving very
> > > distorted output for transcodings of FTA recordings here in Australia.
> > > Prebuilt "nightlies" from Mythbuntu and my own weekly builds from master
> > > both experience this issue. Audio is unaffected.
> > >
> > > All channels are affected except for ABC News 24 and SBS 2.
> > > To describe heavily distorted more: http://i.imgur.com/hfgrn2i.png.
> > >
> > > Here is mythffprobe output for an affected recording file before
> > > transcoding:
> > >
> > > ffprobe version v0.28-pre-2986-g004b87d Copyright (c) 2007-2014 the
> > > FFmpeg developers
> > >    built on Jul 25 2015 11:49:45 with gcc 4.9.2 (Gentoo 4.9.2 p1.0,
> > > pie-0.6.2)
> > >    configuration: --python=python2 --enable-libx264
> > >    libavutil      52. 92.100 / 52. 92.100
> > >    libavcodec     55. 69.100 / 55. 69.100
> > >    libavformat    55. 48.100 / 55. 48.100
> > >    libavdevice    55. 13.102 / 55. 13.102
> > >    libavfilter     4. 11.100 /  4. 11.100
> > >    libswscale      2.  6.100 /  2.  6.100
> > >    libswresample   0. 19.100 /  0. 19.100
> > >    libpostproc    52.  3.100 / 52.  3.100
> > > [mpegts @ 0x6a5020] write_section_data: PID 0x901 CRC error
> > > [mpegts @ 0x6a5020] write_section_data: PID 0x322 CRC error
> > > [mpegts @ 0x6a5020] write_section_data: PID 0x901 CRC error
> > > [mpegts @ 0x6a5020] write_section_data: PID 0x322 CRC error
> > > [NULL @ 0x6ab2a0] start time for stream 3 is not set in
> > > estimate_timings_from_pts
> > > [NULL @ 0x6acf80] start time for stream 4 is not set in
> > > estimate_timings_from_pts
> > > [mpegts @ 0x6a5020] write_section_data: PID 0x901 CRC error
> > > [mpegts @ 0x6a5020] PES packet size mismatch
> > > Input #0, mpegts, from 'fails2.ts':
> > >    Duration: 00:00:08.44, start: 95228.329600, bitrate: 4911 kb/s
> > >      Stream #0:0[0x205]: Video: mpeg2video (Main), yuv420p(tv), 720x576
> > > [SAR 64:45 DAR 16:9], max. 15000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
> > >      Stream #0:1[0x2bc](eng): Audio: mp2, 48000 Hz, stereo, s16p, 192 kb/s
> > >      Stream #0:2[0x245](eng): Subtitle: dvb_teletext
> > >      Stream #0:3[0x901]: Data: dsmcc_b
> > >      Stream #0:4[0x322]: Data: dsmcc_b
> > > Unsupported codec with id 94215 for input stream 2
> > > Unsupported codec with id 1095979811 for input stream 3
> > > Unsupported codec with id 1095979811 for input stream 4
> > >
> > > Output for a non affected recording (from ABC News 24 or SBS 2) has
> > > similar output which I can provide if needed.
> > > Have several samples of affected and non-affected recordings that I can
> > > share.
> > >
> > > Thanks,
> > > Will
> >
> > Have you tried doing a lossless transcode (-m) first?  It might discard
> > all the streams that ffprobe dislikes.
> >
> > John P
> >
> >
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