[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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