[FFmpeg-user] encode five wav files to one Dolby Prologic II encoded file

[Martin Thomas Schrott]

Hi guys,


okay I realiced how to get five separate wav files into one stream:

ffmpeg -i $fl -i $fr -i $fc -i ${bl}_shift.wav -i ${br}_shift.wav 
-filter_complex "[0:0][1:0][2:0][3:0][4:0]amerge=inputs=5, 
aresample=matrix_encoding=dplii" out.wav


but I am still not getting correct dplii encoded channels.


Anyone an idea what I am doing wrong?


* how would I do the phaseshift correctly?

* does matrix_encoding=dplii do the mixing or do I have to add another 
command ... what does matrix_encoding=dplii do exactly?


thanks for any help

Martin



Am 05.03.2023 um 20:18 schrieb Martin Thomas Schrott:
> Hey Guys,
>
>
> after days of reading documentary, searching the net and all lists, 
> trying and loosing, I hope someone here can help me to succeed.
>
>
> I read, some say ffmpeg is not capable of encoding, others say ffmpeg 
> can do it. Some say it misses the phaseshift of the surround channels, 
> others and the docu tell, it can.
>
> So after all I found, I would guess ffmpeg should be able to take five 
> wav files as input and output one wav file in stereo, that is 
> correctly dolby Prologic II encoded including the phaseshifts. But I 
> cannot find how this has to be done to work correctly and there is not 
> a single example anywhere to be found.
>
>
> I tryed countless ways so I post one of them and hope you can guide me 
> where to go or what to change to be successful. :-)
>
>
> This one is with manual phaseshift of the default 0.0 that should be 
> 90 degrees for the two back channels, as nowhere is stated if the 
> matrix_encoding does apply this automatically.
>
> /Applications/ffmpeg -y -i bl.wav -af aphaseshift bl_phaseshift.wav
>
> /Applications/ffmpeg -y -i br.wav -af aphaseshift br_phaseshift.wav
>
>
>
> /Applications/ffmpeg -y -i fl.wav -i fc.wav -i fr.wav -i 
> bl_phaseshift.wav -i br_phaseshift.wav -map 0 -map 1 -map 2 -map 3 
> -map 4 -af aresample=matrix_encoding=dplii surround.wav
>
>
> it gives an error, that a wav file exactly expects one stream. I 
> thought the matrix_encoding would output the five wav files in one 
> stereo stream?
>
> If I change to .aac as output I would get a file, but this would not 
> be a correctly encoded Dolby Prologic II file. This would have 
> distroyed back channels.
>
> Same if I do not apply the phaseshift manually.
>
>
> So I am doing something wrong - anybody here who can help me to find 
> the correct commands?
>
> Would be so thankful. I also did not find a working solution without 
> ffmpeg, so if someone has an alternative this also would be okay - 
> even I would prefer the ffmpeg way :-)
>
>
>
> best wishes,
>
> Martin
>
>
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".