View Full Version : Decoding 3.1 AC3 with AZID or FFmpeg and piping it
Masutin
10th March 2019, 22:21
I need to convert AC3 3.1 (C L R BC) to WAV and then to AAC. eac3to is useless because it requires -simple for 3.1, and this produces FL FR SL SR. FFmpeg does the job. It decodes to 16-bit by default, I don't know which other option to use. And I didn't find if it supports stdout. AZID does, but with the options shown it delivers FL FR SL SR. Also, when piping to QAAC, I get 2.0.
FOR %%A IN (*.ac3) DO AZID -d3/2 -ol,c,r,s -F wav24 "%%A" - | QAAC - -o "%%~nA.m4a
filler56789
11th March 2019, 04:00
That's not 3.1, it's 3(/0)/1.
The channel-layout 3/1 is supported in AAC.
With qaac, you'll need to specify the correct channel-mask
(decimal value = 263, hexadecimal value = 0x0107).
Also, make sure FFmpeg (or something else) outputs the uncompressed stream in the WAVE_FORMAT_EXTENSIBLE format.
tebasuna51
11th March 2019, 04:04
FOR %%A in (*.ac3) DO EAC3TO "%%A" stdout.wav | QAAC -o "%%~nA.m4a" -
work for me without problems, not need -simple and MediaInfo show the m4a like the AC3 3/1.0 input:
Channel layout: C L R Cb
Masutin
12th March 2019, 03:30
In eac3to without -simple, with my AC3 3/1 (C L R Cb) I get "Not available input file format" (The format of the source file could not be detected). By running -test I find that Sonic Audio Decoder is missing. What else can cause the error?
tebasuna51
12th March 2019, 10:37
Please upload the full log.
The Sonic Audio Decoder is not needed at all.
If eac3to show "Not available input file format" maybe that input file is corrupt, but I don't understand how the -simple parameter can make any difference.
Masutin
15th March 2019, 12:47
Thanks! Sorry! The sample AC3 that eac3to couldn't handle without -simple was shortest possible, 32ms. It works with a longer one! Case closed. eac3to rules!
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