[FFmpeg-trac] #210(undetermined:new): bit depth loss with 'lossless' encoding!
FFmpeg
trac at avcodec.org
Tue May 17 04:40:11 CEST 2011
#210: bit depth loss with 'lossless' encoding!
--------------------------+-----------------------
Reporter: Atrocia | Type: defect
Status: new | Priority: critical
Component: undetermined | Version: git
Keywords: | Blocked By:
Blocking: | Reproduced: 0
Analyzed: 0 |
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I have 48 KHz / 24 bit audio files created by the Zoom H1 audio recorder;
e.g.:
$ mediainfo sample.WAV
General
Complete name : sample.WAV
Format : Wave
File size : 2.75 MiB
Duration : 10s 0ms
Overall bit rate : 2 304 Kbps
Audio
ID : 0
Format : PCM
Format settings, Endianness : Little
Codec ID : 1
Codec ID/Hint : Microsoft
Duration : 10s 0ms
Bit rate : 2 304 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Stream size : 2.75 MiB (100%)
When I convert them to flac format, they become 16 bit:
$ ffmpeg -i sample.WAV sample.flac
...
$ mediainfo sample.flac
General
Complete name : sample.flac
Format : FLAC
Format/Info : Free Lossless Audio Codec
File size : 695 KiB
Duration : 10s 0ms
Overall bit rate : 569 Kbps
Writing application : Lavf53.0.3
Audio
Format : FLAC
Format/Info : Free Lossless Audio Codec
Duration : 10s 0ms
Bit rate mode : Variable
Bit rate : 563 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Stream size : 687 KiB (99%)
Writing library : Lavf53.0.3
ffmpeg (git-N-29954-gfc19379) throws this warning - I don't know if it's
relevant:
Incompatible sample format 's32' for codec 'flac', auto-selecting format
's16'
The 'flac' tool, from the flac project, handles these files correctly:
$ flac sample.WAV
...
$ mediainfo sample.flac
General
Complete name : sample.flac
Format : FLAC
Format/Info : Free Lossless Audio Codec
File size : 1.59 MiB
Duration : 10s 0ms
Overall bit rate : 1 336 Kbps
Audio
Format : FLAC
Format/Info : Free Lossless Audio Codec
Duration : 10s 0ms
Bit rate mode : Variable
Bit rate : 1 329 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Stream size : 1.58 MiB (100%)
Writing library : libFLAC 1.2.1 (UTC 2007-09-17)
flac gives this warning - no idea if this is related to the one ffmpeg
gives:
sample.WAV: WARNING: legacy WAVE file has format type 1 but bits-per-
sample=24
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/210>
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