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

[Benjamin Larsson]

zhentan feng wrote:
> 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


Hi, this is the latest version of my patch. This adds the maybe correct
GUID values. To really test this you need to find a wav file with a
corrrect dwChannelMask. And then make sure that the muxer puts the same
mask to the transcoded file. The output file should also be playable in
windows.

MvH
Benjamin Larsson
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