[mythtv-commits] Ticket #12303: transcoding to Nuppelvideo loses audio
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Thu Feb 26 17:24:45 UTC 2015
#12303: transcoding to Nuppelvideo loses audio
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Reporter: ssd.mtv@… | Owner: jyavenard
Type: Bug Report - General | Status: infoneeded_new
Priority: major | Milestone: unknown
Component: MythTV - Mythtranscode | Version: 0.27-fixes
Severity: medium | Resolution:
Keywords: transcode audio | Ticket locked: 0
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Comment (by Nicolas Pöhlmann <nicolas.poehlmann@…>):
Replying to [comment:23 dekarl]:
it seems to be an error when transcoding 5.1 audio channels to mp3-format,
at least wrong frame size is selected for audio.
before [cut down to necessary information]:
ffprobe version 1.2.7 Copyright (c) 2007-2014 the FFmpeg developers
...
Input #0, mpegts, from
'/media/MythTV_Disk2/MythTV/Standard/13120_20150221191000.mpg':
Duration: 01:04:58.66, start: 90506.666933, bitrate: 6079 kb/s
Stream #0:0[0x1a05]: Video: h264 (High), yuv420p, 1280x720 [SAR 1:1
DAR 16:9], 50 fps, 50 tbr, 90k tbn, 100 tbc
Stream #0:1[0x1a06](deu): Audio: ac3, 48000 Hz, 5.1(side), fltp, 448
kb/s
Stream #0:2[0x1a07](fra): Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
Stream #0:3[0x1a08](ger): Subtitle: dvb_teletext
Stream #0:4[0x1a09](deu): Subtitle: dvb_subtitle
Stream #0:5[0x1a0a](fra): Subtitle: dvb_subtitle
Unsupported codec with id 94215 for input stream 3
[dvbsub @ 0x1aae8c0] Invalid extradata, subtitle streams may be combined!
[dvbsub @ 0x1aaf440] Invalid extradata, subtitle streams may be combined!
after [cut down to necessary information]:
ffprobe version 1.2.7 Copyright (c) 2007-2014 the FFmpeg developers
...
[nuv @ 0x1febea0] max_analyze_duration 5000000 reached at 5000000
microseconds
[nuv @ 0x1febea0] Could not find codec parameters for stream 1 (Audio: mp3
(LAME / 0x454D414C), 48000 Hz, 2 channels, s16p, 1411 kb/s): unspecified
frame size
Consider increasing the value for the 'analyzeduration' and 'probesize'
options
[nuv @ 0x1febea0] Estimating duration from bitrate, this may be inaccurate
Input #0, nuv, from
'/media/MythTV_Disk2/MythTV/Standard/13120_20150221191000.nuv':
Duration: 04:50:57.46, start: 0.020000, bitrate: 1411 kb/s
Stream #0:0: Video: mpeg4 (DIVX / 0x58564944), yuv420p, 1280x720, SAR
1:1 DAR 16:9, 50 fps, 50 tbr, 1k tbn, 1k tbc
Stream #0:1: Audio: mp3 (LAME / 0x454D414C), 48000 Hz, 2 channels,
s16p, 1411 kb/s
But this time it's NOT a similar problem like in #11639. it only affects
5.1/x.1 channel transcoding. stereo recordings are NOT affected.
PROBLEM:
The AudioReencodeBuffer frames in the transcode.cpp file [Line 286 and
1338] aren't filled, so that no audio frames at all can be even processed.
I assume that there must be a problem filling them while trying to down
5.1 channels to 2.
As I'm not an audio/lame expert, maybe another one can take a look into
that problem.
Better solution would be if there is someone out which can implement an
option for the mp3-surround extension:
http://en.wikipedia.org/wiki/MP3_Surround
--
Ticket URL: <https://code.mythtv.org/trac/ticket/12303#comment:24>
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