VLC 2.0.1 crashes playing M2TS file

[Chrisj1960]

I have a lot of M2TS files (DVB-T2 transmission streams recorded on a Panasonic PVR in 'DR' mode). I routinely use HandBrake to rip these fils into a format suitable for my Apple TV and as part of that process I use VLC to preview the files. Normally this works just fine buyt there is a particular set of these files that play fine on the PVR but which when ripped with Handbrake have missing audio (specifically audio is present for the pre-program announcement, post-programme announcement and inter-programme advertisement breaks but is missing for all of the actual programme). Video is fine, it is just the audio that has a problem. If I try and play one of these M2TS files using VLC 2.0.1 then VLC crashes at the point where the audio changes. The same behaviour occurs on both Mac OS X and Windows 7. Windows Media Player plays the file without crashing though it does not play any audio at all. My questions is if this is considered a bug (and hence should I open a bug report).

The crash report is too large to include here (web site won't accept it) but can be downloaded from here:

http://dl.dropbox.com/u/6635867/VLC201Crash.txt

Thanks.

[nkoriyama]

Do you mean VLC crashes when audio channel changing?
If so, it's a bug of FAAD2 AAC decoder library and VLC.
When audio channel changing (mono <-> stereo, mono,stereo <-> 5.1ch, etc), sometimes VLC stops playing audio, sometimes VLC crashes.

If audio stops, disable audio (Audio -> Audio Track -> Disable) then select audio (Audio -> Audio Track -> Track *), and you will hear the audio.

[Chrisj1960]

Thanks for the reply. No, that isn't what I mean. The file has two audio tracks. One is AAC/LC/LATM (main audio track) and the other is HE-AAC/LC/LATM (commentary for the visually impaired). The video/audio starts with some pre-programme intro (announcement, advert etc.), then continues with the actual program, then has adverts, then programme, then finishes with more announcements/adverts. If I play the file with VLC 2.0.1 with the main audio track selected then VLC crashes when it reaches the transition from the pre-programme video/audio to the actual programme video/audio. If I play with the secondary audio track selected then the file plays fine except that there is no sound output at all. This is not specific to this file, there is a large series of these files (all the same programme, different episodes) which have this problem. I strongly suspect there is some subtlety about the audio encoding within the stream (for the sections that are the actual programme) that is causing this (and the associated problems when transcoding it with HandBrake). This is supported by the fact that many other programmes recorded on the PVR which have apparently the exact same file/stream format./content play just fine.

Chris

[nkoriyama]

Anyway you can open a bug report, but don't forget to provide a short sample. No sample means no bug.

[nkoriyama]

@Chrisj1960
Thank you for creating ticket 6639, but I forgot the same issue ticket 5433.
It's a known bug of AAC decoder (using libfaac), and I know aac decoder have some issues especially when changing audio channel:
2ch <-> 5.1ch: crash
mono <-> stereo: audio distortion

Ad hoc workaround is deleting libfaad_plugin.dylib in /Applications/VLC.app/Contents/MacOS/plugins.
If you delete it, these issues (audio distortion and crashing ) will disappear.
But when changing 2ch <-> 5.1ch, audio stops. Then, do the following manually:

If audio stops, disable audio (Audio -> Audio Track -> Disable) then select audio (Audio -> Audio Track -> Track *), and you will hear the audio.

or press "L" to change audio track.