@madshi
There seem to be a problem with a AC3 file, it was reported by a staxrip user so I don't have the source but if you want to work on it I might be able to get the file for you.
Code:
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Source file MediaInfo
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F:\Movie.mkv
General
Complete name : F:\Movie.mkv
Format : Matroska
Format version : Version 1
File size : 1.46 GiB
Duration : 56 min 46 s
Overall bit rate : 3 677 kb/s
Encoded date : UTC 2009-06-22 03:44:10
Writing application : mkvmerge v2.4.0 ('Fumbling Towards Ecstasy') built on Nov 7 2008 17:24:23
Writing library : libebml v0.7.8 + libmatroska v0.8.1
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.1
Format, CABAC : Yes
Format, ReFrames : 3 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 56 min 46 s
Bit rate : 3 289 kb/s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
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
Bits/(Pixel*Frame) : 0.149
Stream size : 1.28 GiB (88%)
Writing library : x264 core 67 r1162M f7bfcfa
Language : English
Default : Yes
Forced : No
Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Format, Endianness : Big
Codec ID : A_AC3
Duration : 56 min 46 s
Bit rate mode : Constant
Bit rate : 384 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 spf)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 156 MiB (10%)
Service kind : Complete Main
Default : Yes
Forced : No
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Demux mkv using mkvextract 13.0.0 x64
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C:\StaxRip\Apps\MKVToolNix\mkvextract.exe tracks F:\Movie.mkv 1:"F:\Movie_temp\Movie ID1.ac3" --ui-language en
Extracting track 1 with the CodecID 'A_AC3' to the file 'F:\Movie_temp\Movie ID1.ac3'. Container format: Dolby Digital (AC-3)
Start: 9:08:04 PM
End: 9:08:07 PM
Duration: 00:00:02
General
Complete name : F:\Movie_temp\Movie ID1.ac3
Format : AC-3
Format/Info : Audio Coding 3
File size : 156 MiB
Duration : 56 min 46 s
Overall bit rate mode : Constant
Overall bit rate : 384 kb/s
Audio
Format : AC-3
Format/Info : Audio Coding 3
Format, Endianness : Big
Duration : 56 min 46 s
Bit rate mode : Constant
Bit rate : 384 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 spf)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 156 MiB (100%)
Service kind : Complete Main
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Audio Source File MediaInfo
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General
Complete name : F:\Movie_temp\Movie ID1.ac3
Format : AC-3
Format/Info : Audio Coding 3
File size : 156 MiB
Duration : 56 min 46 s
Overall bit rate mode : Constant
Overall bit rate : 384 kb/s
Audio
Format : AC-3
Format/Info : Audio Coding 3
Format, Endianness : Big
Duration : 56 min 46 s
Bit rate mode : Constant
Bit rate : 384 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 spf)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 156 MiB (100%)
Service kind : Complete Main
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Audio encoding using eac3to 3.31 x86
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C:\StaxRip\Apps\eac3to\eac3to.exe "F:\Movie_temp\Movie ID1.ac3" "F:\Movie_temp\Movie ID1_a1.m4a"
-quality=0.23 -normalize -downStereo -progressnumbers
AC3, 2.0 channels, 0:56:46, 384kbps, 48kHz, dialnorm: -27dB
Removing AC3 dialog normalization...
Decoding with libav/ffmpeg...
Writing WAV...
Creating file "F:\Movie_temp\Movie ID1_a1.m4a.pass1.wav"...
Caution: The WAV file is bigger than 4GB.
Some WAV readers might not be able to handle this file correctly.
Starting 2nd pass...
Reading WAV...
Reducing depth from 64 to 32 bits...
Encoding AAC <0.23> with NeroAacEnc...
Applying 0.95dB gain...
The original audio track has a constant bit depth of 64 bits.
The processed audio track has a constant bit depth of 32 bits.
eac3to processing took 3 minutes, 34 seconds.
Done.
Start: 9:08:08 PM
End: 9:11:43 PM
Duration: 00:03:34
General
Complete name : F:\Movie_temp\Movie ID1_a1.m4a
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (M4A /mp42/isom)
File size : 76.3 MiB
Duration : 2 h 48 min
Overall bit rate mode : Variable
Overall bit rate : 63.4 kb/s
Encoded date : UTC 2017-09-22 01:08:31
Tagged date : UTC 2017-09-22 01:11:42
Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : HE-AAC / LC
Codec ID : 40
Duration : 2 h 48 min
Bit rate mode : Variable
Bit rate : 62.6 kb/s
Maximum bit rate : 77.7 kb/s
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
Stream size : 75.3 MiB (99%)
Writing library : Nero AAC codec 1.5.4.0
Encoded date : UTC 2017-09-22 01:08:31
Tagged date : UTC 2017-09-22 01:11:42