[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
free.
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
sure.
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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