[FFmpeg-user] Dropping audio streams confuses vlc?

[hcoin]

On 4/1/2013 10:32 PM, hcoin wrote:
> On 4/1/2013 12:42 PM, Andrey Aleksandrovich wrote:
>> Meybe your source mpg is broken. Try to demux it first:
>> $ projectx file.mpg -demux
>> (projectx homepage - http://project-x.sourceforge.net/ )
>> and then to make your target file from 2 appropriate sources.
>> ffmpeg -i video.file -i audio.file -vcodec copy -acodec copy output.mpg
>>
>> On 4/1/13, hcoin <hcoin at quietfountain.com> wrote:
>>> On 4/1/2013 11:45 AM, Andrey Aleksandrovich wrote:
>>>> On 4/1/13, hcoin <hcoin at quietfountain.com> wrote:
>>>>> Hi all, thanks for ffmpeg!
>>>>>
>>>>> I'm struggling to drop two of three audio streams from an mpeg2
>>>>> audio+video source, and can't puzzle out my mistake.
>>>>>
>>>>> I've given the following command on a mpeg2 file with one video and
>>>>> three ac3 audio streams.  The source and all three streams play
>>>>> perfectly on vlc.   I want the result to be exactly what was input,
>>>>> except with one audio stream: only the second of the three in the
>>>>> original.   But, when I give the command the result is a file 
>>>>> which when
>>>>> played in vlc shows around 56 or so audio streams, and otherwise
>>>>> produces no sound whatever, though the picture is correct.   Am I 
>>>>> making
>>>>> some newbie mistake?
>>>>>
>>>>> ffmpeg -i sourcevid.mpg -vcodec copy -acodec copy outvid.mpg -map 0.0
>>>>> -map 0.2
>>>>>
>>>>> ffmpeg -i sourcevid.mpg -vcodec copy -acodec copy outvid.mpg -map 0.0
>>>>> -map 0.2 -ac 1
>>>>>
>>>>> Both cases process normally, showing the entire and correct 
>>>>> length, then
>>>>> exiting.  Yet - no sound on playback.
>>>>>
>>>>> I tried it on freebsd 9.1 release, and I tried it on debian wheezy 
>>>>> (0:0
>>>>> and 0:2 instead of 0.0 and 0.2) --  same result.  What have I
>>>>> overlooked?
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Harry
>>>> Try this:
>>>> ffmpeg -i INPUT.file -vcodec copy -acodec copy -map 0:0 -map 0:2
>>>> OUTPUT.file
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>>> Thanks for the quick response.   The ffmpeg processing was normal. The
>>> video was normal.  vlc reports 26 audio streams.  No sound was
>>> produced.  Same as before, basically, though the number of audio 
>>> streams
>>> in the output file (which should be 1) is 26 instead of 50 something on
>>> my prior run.   Actually I checked it again during the same vlc
>>> playback, somehow the number of audio streams has grown to 72 now.
>>> mplayer too produces no sound.  Both vlc and mplayer work normally on
>>> the source mpg.
>>>
>>>
>>>
>>>
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>
> Well, some more detail and an interesting development.
>
> As I wrote, both vlc and mplayer play the whole original thing 
> perfectly allowing any audio stream to be chosen.  In my world that 
> means 'no file corruption'.    Project-x completed and managed to 
> produce audio and video files that left out a huge chunk of the middle 
> of the file.  But, the 'demux' idea worked with ffmpeg.   It split the 
> whole file into a video only mpg, and one ac3 stream. Both the broken 
> out files played perfectly.
>
> Here's the interesting bit.  When I gave this command:
>
> ffmpeg -i video.mpg -i audio.ac3 -acodec copy -vcodec copy whole_show.mpg
>
> The result was identical to my initial failed runs:  No audio produced 
> by the combined result, and vlc shows 56 audio streams.
>
> So, either I've missed something obvious, or ffmpeg can't handle 
> muxing together an mpeg2 file and an ac3 audio stream.
>
> Or?
>
>
>
>
>
>
>
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> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user

Replying to my own post:

While the command:

ffmpeg -i video.mpg -i audio.ac3 -acodec copy -vcodec copy whole_show.mpg

fails as noted above,

ffmpeg -i video.mpg -i audio.ac3 -acodec copy -vcodec copy whole_show.mp4

works.

Would those who know how alert whoever it is that fixes ffmpeg bugs?

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