Opened 5 years ago

Last modified 6 months ago

#3595 open enhancement

Support >6 channels in E-AC-3 audio encoder

Reported by: 11rcombs Owned by:
Priority: wish Component: avcodec
Version: git-master Keywords: eac3
Cc: LigH, rodger.combs@gmail.com, j.kis@me.com, hoffbrinkle@hotmail.com Blocked By:
Blocking: Reproduced by developer: yes
Analyzed by developer: no

Description

E-AC-3 supports up to 15 full-bandwidth channels, but libavcodec's encoder currently doesn't support 6.1 and 7.1 channel layouts. Do these layouts just need to be added to ff_ac3_channel_layouts, or would this require additional work on the encoder?

Attachments (1)

snip.eac3 (500.0 KB) - added by LigH 3 years ago.
7.1 channel Blu-ray E-AC-3 with 5.1 AC-3 core and 2 dependent substreams

Download all attachments as: .zip

Change History (11)

comment:1 Changed 5 years ago by cehoyos

  • Priority changed from minor to wish
  • Reproduced by developer set
  • Status changed from new to open
  • Summary changed from Support >5 channels in E-AC-3 audio to Support >6 channels in E-AC-3 audio

comment:2 follow-up: Changed 3 years ago by LigH

This does not only belong to the E-AC-3 encoder, but also to the decoder or the format recognition in general. There is a report in the German doom9/Gleitz video forum that ffmpeg does not even recognize a 7.1 channel Blu-ray audio stream correctly, which consists of a 5.1 AC-3 core and additional E-AC-3 channels. It may have been related to a slightly older version; a rather current ffmpeg version (N-81308-g369ed11, 2016-08-09) prints a warning that it will handle only the 5.1 core:

[eac3 @ 0000000002a8f900] Dependent substream decoding is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[eac3 @ 0000000002a8f900] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)

Possibly relevant: MediaInfo? does not recognize it correctly either (e.g. reports an obviously improbable bitrate of 500 bytes per second).

Changed 3 years ago by LigH

7.1 channel Blu-ray E-AC-3 with 5.1 AC-3 core and 2 dependent substreams

comment:3 Changed 3 years ago by cehoyos

  • Cc LigH added

Is this the one sample we know about (from a demo disk) or a new file?

comment:4 Changed 3 years ago by LigH

AFAIK it's a new file, extracted from a Blu-ray by a Gleitz forum member.

http://forum.gleitz.info/showthread.php?47670-e-ac3-richtig-convertieren

comment:5 Changed 3 years ago by cehoyos

Then please ask for a longer sample that provides actual audible sound (at least 2,5M) and ask which Bluray this is.

Last edited 3 years ago by cehoyos (previous) (diff)

comment:6 Changed 3 years ago by cehoyos

Two minute eac3 7.1 sample (that does not come from the demo disk) uploaded to http://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket3595/

comment:7 in reply to: ↑ 2 Changed 3 years ago by dcxero

Replying to LigH:

Possibly relevant: MediaInfo? does not recognize it correctly either (e.g. reports an obviously improbable bitrate of 500 bytes per second).

MediaInfo? only seems to have a bug reading 7.1 Dolby Digital Plus tracks authored using the Blu-ray Disc profile. It can read 7.1 Dolby Digital Plus tracks authored using the standard profile (which is used more for software and file/streaming distribution)

Here is a Standard profile 7.1 sample: https://www.datafilehost.com/d/ae18d85c

Version 0, edited 3 years ago by dcxero (next)

comment:8 Changed 17 months ago by richardpl

  • Summary changed from Support >6 channels in E-AC-3 audio to Support >6 channels in E-AC-3 audio encoder

comment:9 Changed 15 months ago by johnesz

  • Cc j.kis@me.com added

comment:10 Changed 6 months ago by hoffer

  • Cc hoffbrinkle@hotmail.com added
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