[FFmpeg-devel] Add waveformat extensible support in wav muxer (SoC qualification task)

zhentan feng spyfeng
Thu Mar 26 18:45:14 CET 2009


Hi

2009/3/26 Benjamin Larsson <banan at ludd.ltu.se>

> zhentan feng wrote:
>
>> Hi
>>
>> 2009/3/26 Michael Niedermayer <michaelni at gmx.at>
>>
>>
>>
>>> On Thu, Mar 26, 2009 at 01:19:00AM +0800, zhentan feng wrote:
>>>
>>>
>>>> Hi,
>>>>
>>>> Here is patch for the small task of qualification tasks NO.30.
>>>> Based on the work of Benjamin Larsson, I generated the pathc as below.
>>>>      I think it must need further modifies.
>>>>
>>>>
>>> yes, iam not sure if this or benjamins patch was better
>>>
>>>
>>>
>>
>>
>> I downloaded the 6-channel wav file from:
>>
>> http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/Samples/Microsoft/6_Channel_ID.wav
>>
>> ( and other typr wav files can acess here :
>> http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/Samples.html )
>>
>> 1) then I run ./ffmpeg_g -i 6_Channel_ID.wav channel4.wav
>>
>> I get the error:
>> Resampling with input channels greater than 2 unsupported.
>>
>> so I run another command:
>> 2) ./output_example test.wav
>> ./ffmpeg_g -i test.wav -ac 4 ch4.wav
>>
>> and enc->channels is 4, however enc->channel_layout is 0.
>>
>>
>>
>> Finally, I have 2 questions:
>>
>> 1) how to test the muxer works correctly?
>>
>>
>
> When the muxer works correctly it should be possible to transcode a wav
> file that contains the wavformatextensible header.
>
>  2) where to specify the enc->channel_layout?
>>
>>
>
> It should be filled in by ffmpeg.c.
>

I debug the commandline:
./ffmpeg_g -i test.wav -ac 4 4ch.wav

and found that the enc->channel_layout value is assigned from the input file
channel_layout. In this case, it is 0.
and it seems that "-channel_layout" option doesn't work.

1) is it need to refresh the channel_layout value according to the channels
in ffmpeg.c or in put_wav_header()?
2) any tools to examine the output file is correct?

zhentan feng
-- 
Best wishes~



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