[FFmpeg-trac] #8770(ffmpeg:new): SACD DST (dff extension) sometimes produces errors

FFmpeg trac at avcodec.org
Wed Jul 1 13:38:43 EEST 2020

#8770: SACD DST (dff extension) sometimes produces errors
             Reporter:  MelkorLord   |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  ffmpeg       |                  Version:  git-
             Keywords:  sacd dst     |  master
  dff                                |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
 I have a bunch of DSD files from my SACD collection ripped a long time ago
 with `sacd-ripper` https://github.com/sacd-ripper/sacd-ripper using the
 command line `sacd_extract -i sacd.iso -m -p` which produces `Philips
 DSDIFF` according to the usage help.

 `sacd_extract -i sacd.iso -m -s` produces `Sony DSF` files from the very
 same SACD ISO and it's faster but resulting files are way bigger.

 When I try to turn them into RF64 WAV files, some DFF (dst) files produce
 errors but DSF files, identified `Stream #0:0: Audio: dsd_lsbf_planar,
 352800 Hz, 5.1, fltp, 16934 kb/s` by FFMPEG are absolutely clean and error

 To (try to) validate that all files are clean, I used `odio-sacd`
 https://tari.in/www/software/odio-sacd/ which is a DST/DFF converter and
 it produces WAV files (non RF64) out of DFF files free of any error.

 The command line is `odio-sacd -i "music_file.dff" -r 176400`

 On the lower volume parts of the tracks, the FFMPEG WAV files have cracks
 and pops around the timelines where the decoding errors occurred. And the
 WAV files are always a tiny bit shorter in size and thus in time by 10's
 of milliseconds on those 5.1 files.

 So I wonder if something is wrong with FFMPEG's DST decoder or if `odio-
 sacd` silently ignores them and mutes them, I have no way of knowing for

 From all the SACD ISOs I have, there's a pattern : For any given ISO, I
 either get errors on a lot of DFF or none of them. I have a lot of DFF
 files which decode cleanly with FFMPEG. But, if at least one DFF file in a
 given ISO produces decoding errors, I can be sure some of the next tracks
 will also produce errors. I couldn't find a pattern among SACD sources
 though (different artists, producers, etc)

 FFMPEG's test command line is:
 `./ffmpeg-git-20200617 -report -i "music_file.dff" -codec:a pcm_s24le -ar
 176400 -rf64 always -f null -`

 The report is attached.

 If needed, I can send DFF files (300~500 MB each) to the FTP server, both
 working and producing decoding errors, just ask :-)

Ticket URL: <https://trac.ffmpeg.org/ticket/8770>
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