[FFmpeg-devel] [PATCH v4 0/9] avformat: wav-s337m support + new probe_stream option

[Nicolas Gaullier]

>> - contribution: mpegts (or dvb for satt etc.) with s302m data -> s337m 
>> (this could be interesting for ffmpeg to support it)
>
>I believe we only had such samples until recently.

With things moving from SDI to IP, I think this is going to be commonplace. I have two s302m samples with DolbyE 20 bits, one muxed in AES 20 bits, another in AES 24 bits, I can share short samples.

>> >> * patch 9 : AVOption to disable codec auto-detect : it seems it is 
>> >> a general request from many users, and it is also critical here for dolby_e as many broadcasters will still need to just pass-through dolby_e data as they already do.
>> >> Thus, the patchset 2,3,4,5,6,7 should not be applied without the last patch 9 applied quickly behind...
>> >
>> >As said, this surprises me, please elaborate.
>> >
>> Most of the time, broadcast users just want to pass-through dolby E
>
>What I meant was:
>What did you try to pass-through (command line)?
>I still believe that your new option is not necessary or at least not needed for this use-case (but I may of course be wrong).

Here is one of my personal real-life use cases : we have a big old archive with .mpg files that holds mp2 stereo audios plus additionnal .wav files for titles that provide DolbyE (those two formats were choose because they were the best mezzanine formats, the most supported).
Now, I typically wants to build a fresh new mxf holding the DolbyE :
ffmpeg -i input.mpg -i input_1.wav -map 0:v -map 1 -c copy output.mxf
This fails because dolby_e is not supported by the current mxf wrapper (nor the 44.8KHz of my DolbyE @25fps).

So I have to use the new option:
ffmpeg -i input.mpg -probe_streams 0 -i input_1.wav -map 0:v -map 1 -c copy output.mxf

Ouput.mxf will be generated as a standard mxf with pcm audio, which is fine (Dolby E signalisation in mxf is possible but very rarely used in my experience - aside ZDF).
Note many people (I would think I am not the only one) already use scripts to pass-through DolbyE data with ffmpeg. We will have to update our command lines to insert the new -probe_stream, which is ok, but indeed this is really necessary otherwise some works that could be done in earlier/current ffmpeg will not be possible to do in future ffmpeg.

Nicolas