Opened 17 years ago
Closed 15 years ago
#5016 closed defect (invalid)
AVFormat Decoder attempts to play zero bitrate video streams
| Reported by: | Owned by: | Janne Grunau | |
|---|---|---|---|
| Priority: | minor | Milestone: | unknown |
| Component: | MythTV - Video Playback | Version: | 0.21-fixes |
| Severity: | medium | Keywords: | DVB-S MPEG2 playing problem |
| Cc: | Ticket locked: | no |
Description
Hi!
I've installed MythTV few days ago and get the following trouble: Some of free (not encrypted) DVB-S channels can't be played my mythfrontend. Same time if I record some video by mythbackend the output file may be played by MPlayer or Windows media player, but mythfrontend can't play these files. I've tried MythTV release-0.21-fixes, trunk (16745) - same result. I'm attaching two log files and posting two .mpg samples to rapidshare (files' sizes are 20MB and 27MB).
Samples:
http://rapidshare.com/files/101416870/2900_20080322131400.mpg http://rapidshare.com/files/101419702/7700_20080322131500.mpg
Attachments (4)
Change History (16)
comment:1 Changed 17 years ago by
Tried to transcode these files by ffmpeg with -vcodec copy and -acodec copy options to leave video and audio streams unchanged, then transcoded file can be normally played my mythfrontend's internal player.
So it looks like demuxer problem of internal player.
comment:2 Changed 17 years ago by
There is some problems with stream type detection. as MPlayer shows attached files contetns three streams: stream 0 - type 0xffffffff (what is it?), stream 1 - type 0x00000002 (VIDEO_MPEG2) and stream 2 - 0x50 (AUDIO_MP2). Mythtv detects and treats stream 0 as MPEG1 video with bitrate 0. This should be fixed at stream type detection stage, but I can't find where it is done :-) I put some additional checks in avformatdecoder.cpp preventing video streams with bitrate 0 from playing. This check should be helpful with other situations when stream type is misrecognized.
Attached file is avformatdecoder.diff against svn trunk rev 16804.
This is temporary fix, maybe someone find better solution? (at stream type detection stage).
comment:3 Changed 17 years ago by
| Milestone: | unknown → 0.22 |
|---|
comment:4 Changed 17 years ago by
| Component: | mythtv → Video Playback |
|---|---|
| Owner: | changed from Isaac Richards to stuartm |
| Status: | new → accepted |
| Summary: | Some DVB-S channels can't be played by mythfrontend. → AVFormat Decoder attempts to play zero bitrate video streams |
comment:5 Changed 17 years ago by
The following from the ffmpeg documentation means I'm not sure about the proposed fix - "bit_rate: 0 or some bitrate if this info is available in the stream". The implication being that there will be times when valid streams report a bitrate of zero.
A better solution would be to look at the bitrate of all video streams first and only ignore the zero bitrate stream if a non-zero stream can be found. This could only be done if ScanStreams? is reorganised, which is a good idea anyway, but it needs some discussion with the over devs first.
comment:6 Changed 17 years ago by
| Owner: | changed from stuartm to janneg |
|---|---|
| Status: | accepted → assigned |
comment:7 Changed 16 years ago by
| Milestone: | 0.22 → 0.21.1 |
|---|---|
| Owner: | changed from janneg to Janne Grunau |
| Status: | assigned → accepted |
comment:8 Changed 16 years ago by
| Milestone: | 0.21.1 → 0.22 |
|---|
comment:9 Changed 16 years ago by
See #6122, a DVB radio channel which includes an mpeg-2 video stream with reported bitrate of 90Kbps.
comment:10 Changed 16 years ago by
| Component: | Video Playback → MythTV - Video Playback |
|---|
comment:11 Changed 16 years ago by
| Milestone: | 0.22 → unknown |
|---|---|
| Priority: | critical → minor |
| Status: | accepted → infoneeded |
please recheck if the the problem still persist with current trunk and reupload the samples.
comment:12 Changed 15 years ago by
| Resolution: | → invalid |
|---|---|
| Status: | infoneeded → closed |
30 days without response.
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