[FFmpeg-trac] #6543(undetermined:new): ATRAC Advanced Lossless decoding, not bit-exact?

FFmpeg trac at avcodec.org
Wed Jul 19 19:32:22 EEST 2017


#6543: ATRAC Advanced Lossless decoding, not bit-exact?
-------------------------------------+-------------------------------------
             Reporter:  macdavis     |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
  atrac3plusal                       |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 I converted "dts_sample.flac" to ATRAC Advanced Lossless
 ("dts_sample.oma")  with SonicStage (Version 4.3, download link [ftp://ftp
 .vaio-link.com/pub/Downloads/SO/A/SST/SOASST-01198207-UN.exe]). Then,
 using ffmpeg to convert "dts_sample.oma" back to Flac. However, the
 conversion seems not bit-exact.

 I checked the original Flac with Adobe Audition. Here is the original
 one's amplitude statistics.


 {{{
         Channel 1       Channel 2
 Peak Amplitude: -0.09 dB        -1.08 dB
 True Peak Amplitude:    -0.09 dBTP      -1.08 dBTP
 Maximum Sample Value:   25664   27834
 Minimum Sample Value:   -32440  -28930
 Possibly Clipped Samples:       0       0
 Total RMS Amplitude:    -24.68 dB       -24.34 dB
 Maximum RMS Amplitude:  -8.98 dB        -7.12 dB
 Minimum RMS Amplitude:  -84.55 dB       -83.76 dB
 Average RMS Amplitude:  -38.58 dB       -38.89 dB
 DC Offset:      0.05 %  0.02 %
 Measured Bit Depth:     16      16
 Dynamic Range:  75.57 dB        76.65 dB
 Dynamic Range Used:     73.20 dB        74.15 dB
 Loudness (Legacy):      -12.45 dB       -11.96 dB
 Perceived Loudness (Legacy):    -15.06 dB       -11.62 dB
 ITU-R BS.1770-3 Loudness: -19.83 LUFS

 0dB = FS Square Wave
 Using RMS Window of 50.00 ms
 Account for DC = true
 }}}

 Here is the amplitude statistics of Flac converted from "dts_sample.oma"

 {{{
         Channel 1       Channel 2
 Peak Amplitude: -0.03 dB        -1.13 dB
 True Peak Amplitude:    -0.03 dBTP      -1.13 dBTP
 Maximum Sample Value:   25292.57        28165.01
 Minimum Sample Value:   -32656.77       -28762.40
 Possibly Clipped Samples:       0       0
 Total RMS Amplitude:    -24.71 dB       -24.38 dB
 Maximum RMS Amplitude:  -9.00 dB        -7.22 dB
 Minimum RMS Amplitude:  -84.51 dB       -84.95 dB
 Average RMS Amplitude:  -38.73 dB       -39.15 dB
 DC Offset:      0.05 %  0.01 %
 Measured Bit Depth:     24      24
 Dynamic Range:  75.51 dB        77.72 dB
 Dynamic Range Used:     73.60 dB        75.05 dB
 Loudness (Legacy):      -13.47 dB       -11.95 dB
 Perceived Loudness (Legacy):    -18.84 dB       -11.55 dB
 ITU-R BS.1770-3 Loudness: -19.84 LUFS

 0dB = FS Square Wave
 Using RMS Window of 50.00 ms
 Account for DC = true
 }}}


 How to reproduce:
 {{{
 ffmpeg -i /Volumes/New\ Volume/sony\ lossless/dts_sample.oma -c:a flac
 -compression_level 12 /Volumes/New\ Volume/sony\
 lossless/dts_sample_oma_to_flac.flac
 ffmpeg version 3.3.git Copyright (c) 2000-2017 the FFmpeg developers
   built with Apple LLVM version 8.1.0 (clang-802.0.42)
   configuration: --optflags=-Ofast --prefix=/usr/local --extra-
 cflags='-march=haswell -mtune=intel -m64 -minline-all-stringops -fomit-
 frame-pointer -fforce-addr -finline-functions -funit-at-a-time -funroll-
 loops -ffunction-sections -fdata-sections -Ofast -pipe -fomit-frame-
 pointer -ftree-vectorize' --target-os=darwin --arch=x86_64 --cpu=haswell
 --disable-runtime-cpudetect --disable-debug --disable-opencl --disable-
 avdevice --disable-ffplay --disable-ffprobe --disable-postproc --disable-
 ffserver --disable-devices --disable-avresample --disable-indev=qtkit
 --disable-doc --enable-pthreads --enable-version3 --enable-hardcoded-
 tables --enable-gpl --enable-nonfree
   libavutil      55. 67.100 / 55. 67.100
   libavcodec     57.100.103 / 57.100.103
   libavformat    57. 75.100 / 57. 75.100
   libavfilter     6. 95.100 /  6. 95.100
   libswscale      4.  7.101 /  4.  7.101
   libswresample   2.  8.100 /  2.  8.100
 Input #0, oma, from '/Volumes/New Volume/sony lossless/dts_sample.oma':
   Metadata:
     title           : dts_sample
     OMG_TRACK       : 0
     OMG_TIT2S       : dts_sample
     TLEN            : 18894
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Audio: atrac3pal ([33][0][0][0] / 0x0021), 44100 Hz,
 stereo, fltp
 Stream mapping:
   Stream #0:0 -> #0:0 (atrac3pal (atrac3plusal) -> flac (native))
 Press [q] to stop, [?] for help
 [flac @ 0x7ffb1a801800] encoding as 24 bits-per-sample
 Output #0, flac, to '/Volumes/New Volume/sony
 lossless/dts_sample_oma_to_flac.flac':
   Metadata:
     title           : dts_sample
     OMG_TRACK       : 0
     OMG_TIT2S       : dts_sample
     TLEN            : 18894
     encoder         : Lavf57.75.100
     Stream #0:0: Audio: flac, 44100 Hz, stereo, s32 (24 bit), 128 kb/s
     Metadata:
       encoder         : Lavc57.100.103 flac
 size=    2711kB time=00:00:18.94 bitrate=1172.2kbits/s speed=20.1x
 video:0kB audio:2703kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.302080%
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6543>
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