[FFmpeg-user] stereo upmix and matrix_encoding

[Martin Thomas Schrott]

ok got it. :-)

had to add -ac 6 before surround  otherwise it would output a stereo stream.


thanks!

Martin



Am 16.06.2023 um 13:51 schrieb Martin Thomas Schrott:
> Hi folgs,
>
>
> I would like to upmix a stereo file to a surround one and came accross 
> the "surround" filter in ffmpeg documentation. Seems this does what I 
> would like to do, but I could not find how to use it correctly as it 
> seems.
>
>
> I would like to combine it with aresample=matrix_encoding=dplii to get 
> a correct surround wav out.
>
>
> So I tried to use a -filter_complex with my stereo as an input file.
>
> And send the output from surround to aresample for encoding.
>
>
> -i myfile.wav -filter_complex "[0:a]surround[a1]; 
> [a1]aresample=matrix_encoding=dplii" outfile.wav
>
>
> The file still is normal stereo and ignored by decoders. :-(
>
> I also tried to add ichl=5.1 to the aresample - which also did not help.
>
>
> Could anyone please either tell me, what I am doing wrong,
>
> or give me another working way to upmix the file and encode it correctly?
>
>
> (I know this way the phaseshift is missing - so if someone could 
> include that too, I would appreciate that of course) ;-)
>
>
> If combining does not work properly I also would be fine with 
> outputing a six channel wav or six separate wave files, as I have the 
> code to encode this correctly. :-)
>
>
> Thanks for any hint and help!
>
>
> cheers
>
> Martin
>
>
>
>
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