John L wrote:
Please test the following:
$ ffmpeg -i inter.dts -rematrix_maxval 1.0 -ac 2 out.ac3
$ ffmpeg -i inter.dts -rematrix_maxval 1.0 -ac 2 out.mp3
$ ffmpeg -i inter.dts -rematrix_maxval 1.0 -ac 2 -acodec pcm_f32le out.wav
I ran all three as requested, including '-loglevel debug'. All three resulting
files resulted in poor quality audio as before. the filtergraph output does
show something different however, but the resulting audio is still terrible and
indistinguishable from before.
That's strange, it seems to do the correct thing for me (only tested
last one).
I notice typical of "loud movie" dts the master sample is quite extreme
to start with (and clipped a bit by studio I think).
But ignoring that the downmix with -rematrix_maxval 1.0 is the same for
me as using a signed wav.
"Looking" with sox
ffmpeg -i inter.dts -rematrix_maxval 1.0 -ac 2 -acodec pcm_f32le outf-1.wav
sox outf-1.wav -n stats
sox WARN wav: wave header missing FmtExt chunk
Overall Left Right
DC offset -0.000397 -0.000397 -0.000138
Min level -0.986728 -0.977729 -0.986728
Max level 0.988566 0.974450 0.988566
Pk lev dB -0.10 -0.20 -0.10
RMS lev dB -11.54 -11.47 -11.60
RMS Pk dB -4.73 -4.73 -4.97
RMS Tr dB -36.11 -36.08 -36.11
Crest factor - 3.66 3.76
Flat factor 0.00 0.00 0.00
Pk count 2 2 2
Bit-depth 32/32 32/32 32/32
Num samples 1.44M
Length s 29.995
Scale max 1.000000
Window s 0.050
Without -rematrix_maxval 1.0
sox outf-0.wav -n stats
sox WARN wav: wave header missing FmtExt chunk
Overall Left Right
DC offset -0.005071 -0.005071 -0.002057
Min level -1.000000 -1.000000 -1.000000
Max level 1.000000 1.000000 1.000000
Pk lev dB 0.00 0.00 0.00
RMS lev dB -5.62 -5.61 -5.63
RMS Pk dB -0.79 -0.79 -1.03
RMS Tr dB -28.46 -28.42 -28.46
Crest factor - 1.91 1.91
Flat factor 45.34 46.05 44.52
Pk count 222k 228k 216k
Bit-depth 32/32 32/32 32/32
Num samples 1.44M
Length s 29.995
Scale max 1.000000
Window s 0.050
sox WARN sox: `outf-0.wav' input clipped 443634 samples
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