[FFmpeg-trac] #8711(ffmpeg:new): Wrong 'Stream mapping' selection

[FFmpeg]

#8711: Wrong 'Stream mapping' selection
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             Reporter:  giuliano  |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  ffmpeg    |                  Version:  4.2
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 Summary of the bug:
 I'm trying to save a multi variant live streaming (input) using as output
 a HLS format.
 The problem is that the result is a video-audio out of sync.

 The input live streaming has a HLS format with several variants.
 From the ffmpeg output log I can see:
 ...
 Program 0
     ...
     Stream #0:0: Data: timed_id3 (ID3  / 0x20334449)
     ...
     Stream #0:1: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p,
 704x396 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
     ...
     Stream #0:2: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz,
 stereo, fltp
 Program 1
     ...
     Stream #0:3: Data: timed_id3 (ID3  / 0x20334449)
     ...
     Stream #0:4: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p,
 512x288 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
     ...
     Stream #0:5: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz,
 stereo, fltp
     ...
 Program 2
     ...
     Stream #0:6, 1, 1/90000: Data: timed_id3 (ID3  / 0x20334449), 0/1
     ...
     Stream #0:7, 21, 1/90000: Video: h264 (Main), 1 reference frame
 ([27][0][0][0] / 0x001B), yuv420p(left), 512x288 [SAR 1:1 DAR 16:9], 0/1,
 25 fps, 25 tbr, 90k tbn, 50 tbc
     ...
     Stream #0:8, 36, 1/90000: Audio: aac (LC) ([15][0][0][0] / 0x000F),
 48000 Hz, stereo, fltp
     ...

 In case I do not specify the 'map' ffmpeg parameter, ffmpeg is selecting
 streams from different 'Programs', i.e. Stream #0:7  and Stream #0:2, and
 we have the video-audio out of sync.

 In case I specifies the 'map' ffmpeg parameter selecting streams belonging
 to the same 'Program', i.e. Stream #0:4  and Stream #0:5, we do NOT have
 anymore the video-audio out of sync.
 The problem with this solution is that, in case the variants/streams of
 the input live streaming changes, I have always to change my map
 parameters.

 The fix I'm asking to be evaluated, to avoid the video-audio out of sync,
 is the following:
 In case the 'map' parameter is not specified, ffmpeg should select streams
 belonging to the same 'Program'.
 Does it has sense for you?

 How to reproduce:
 {{{
 % ffmpeg -v 9 -loglevel 99 -nostdin -re -i
 http://mediapolis.rai.itelinker/relinkerServlet.htm?cont=746966 -t 30 -c:v
 copy -c:a copy -f segment -segment_list /.../liveRecorder.list
 -segment_time 10 -segment_atclocktime 1 -strftime 1
 /.../liveRecorder_%Y-%m-%d_%H-%M-%S_%s.ts > outputLog.txt 2>&1

 ffmpeg version 4.2.2

 built on Ubuntu 18.04.4 LTS
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8711>
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