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Avidemux 2.7.0 audio bug

Started by Zhanat, March 18, 2018, 06:59:04 AM

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Zhanat

Hello! I have a problem with audio in Avidemux 2.7.0 x32 win. The sound is reproduced with snippets. In Avidemux 2.6.20 x32 Win. There is no such problem. Sample videos:http://rgho.st/private/8KFrFbzTz/929fe10fdf2b085d18b9483aa01e3943
MediaInfo:
General
Unique ID                   : 298486162568430481418688468100542944653 (0xE08E58066514ED0C19790A5545F4D58D)
Complete name               : D:\edit.mkv
Format                      : Matroska
Format version              : Version 4 / Version 2
File size                   : 4.14 MiB
Duration                    : 49s 216ms
Overall bit rate            : 706 Kbps
Writing application         : Lavf57.71.100
Writing library             : Lavf57.71.100 / Lavf57.71.100
ErrorDetectionType          : Per level 1

Video
ID                          : 1
Format                      : AVC
Format/Info                 : Advanced Video Codec
Format profile              : High@L4.1
Format settings, CABAC      : Yes
Format settings, ReFrames   : 10 frames
Codec ID                    : V_MPEG4/ISO/AVC
Duration                    : 49s 216ms
Width                       : 768 pixels
Height                      : 320 pixels
Display aspect ratio        : 2.40:1
Frame rate mode             : Constant
Frame rate                  : 23.976 (24000/1001) fps
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Default                     : Yes
Forced                      : No
DURATION                    : 00:00:49.216000000

Audio
ID                          : 2
Format                      : AAC
Format/Info                 : Advanced Audio Codec
Format profile              : HE-AAC / LC
Codec ID                    : A_AAC
Duration                    : 49s 216ms
Channel(s)                  : 2 channels
Channel positions           : Front: L R
Sampling rate               : 48.0 KHz / 24.0 KHz
Frame rate                  : 23.438 fps (1024 spf)
Compression mode            : Lossy
Delay relative to video     : -46ms
Default                     : Yes
Forced                      : No
DURATION                    : 00:00:49.105000000


eumagga0x2a

You see this issue in the first place because 2.7.0 for Windows shipped for the first time without the FAAD decoder and library (libfaad and/or its headers were not present in the build node, generally the goal is to do without FAAD in favor of the bundled FFmpeg). As far as I understand the situation, the audio uses sprectral band replication which is not declared in the MKV, so we end up with half a sample rate (24 kHz instead of 48 kHz). The FAAD decoder implements a workaround, the FFmpeg based one does not.

eumagga0x2a

Mean has just implemented a deeper check in the MKV demuxer, fixing this issue when using the FFmpeg (lavc) audio decoder: [mkv] Recheck chan and fq by decoding extradata if they are there.

You may want to try a nightly once a build dated 2018-03-18 or later has been uploaded.

Zhanat