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[Pyroh]

I've been having this issue where JRiver is supposedly recognising a 16 bit AC3 audio stream in an MKV as a 32 bit stream. According to MediaInfo the stream's bit depth is 16 bit so I'm quite sure that it's a bug in JRiver. I've tested it on multiple MKVs so far, all using AC3 audio as far as I'm aware. Here's a few items for reference:

Full MediaInfo for one of the videos:

Code: [Select]

General
Unique ID                                : 289377821056334509080259217150687031987 (0xD9B4241DE8FF35907B5895940BC3B2B3)
Complete name                            : D:\MKV\SpartacusS2E01.mkv
Format                                   : Matroska
Format version                           : Version 2
File size                                : 1.45 GiB
Duration                                 : 56mn 1s
Overall bit rate                         : 3 713 Kbps
Encoded date                             : UTC 2012-01-28 06:07:17
Writing application                      : mkvmerge v3.0.0 ('Hang up your Hang-Ups') built on Apr 19 2010 11:58:49
Writing library                          : libebml v0.7.7 + libmatroska v0.8.1

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 5 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 56mn 1s
Bit rate                                 : 3 255 Kbps
Width                                    : 1 280 pixels
Height                                   : 720 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 23.976 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.147
Stream size                              : 1.27 GiB (88%)
Writing library                          : x264 core 120 r2146 bcd41db
Encoding settings                        : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=18.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language                                 : English
Default                                  : No
Forced                                   : No

Audio
ID                                       : 2
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Codec ID                                 : A_AC3
Duration                                 : 56mn 1s
Bit rate mode                            : Constant
Bit rate                                 : 384 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Stream size                              : 154 MiB (10%)
Default                                  : Yes
Forced                                   : No

The error as shown in audio path:



My output settings (tempo and pitch are on because Videoclock):

[Matt]

We're reporting what LAV Audio decoder is delivering.

It's harmless if it delivers extra bits, so I don't think there's any reason for concern.

[Hendrik]

AC3 has no fixed bit depth. What MediaInfo reports is just mis-information.

Its a lossy encoding, and most lossy formats are decoded to 32-bit floating point, for maximum quality.
Only lossless formats have an actual bitdepth, like TrueHD, DTS-HD MA, FLAC, ALAC, etc..

[Matt]

Thanks nevcairiel.

We stopped reporting a bitdepth for lossy audio formats on Audio Path because it caused too much confusion.  In one funny thread a user was insulting us for not knowing the correct bitdepth

There's a little more information on this topic here:
http://wiki.jriver.com/index.php/Audio_Bitdepth#Bitdepth_of_Lossy_Formats

[jmone]

Only lossless formats have an actual bitdepth, like TrueHD, DTS-HD MA, FLAC, ALAC, etc..

And WAV of course!

Matt nice write up in the Wiki....of course many of the Audiophiles will disagree....

[Hendrik]

And WAV of course!

I wrote "etc" for a reason, i'm sure there are many other lossless formats out there. :p