[mythtv-commits] Ticket #12728: Mythtranscode reporting incorrect audio properties
MythTV
noreply at mythtv.org
Thu Apr 14 17:46:11 UTC 2016
#12728: Mythtranscode reporting incorrect audio properties
-----------------------------------------+---------------------------------
Reporter: JP Briggs <jp.briggs@…> | Owner: jyavenard
Type: Bug Report - General | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - Mythtranscode | Version: 0.27.6
Severity: medium | Keywords: mythtranscode audio
Ticket locked: 0 |
-----------------------------------------+---------------------------------
I have a recording I am trying to transcode lossless to strip commercials.
From there, I will re-encode using HandBrake.
The original recording's audio is reported thusly (via mediainfo)
{{{
Audio #1
ID : 6302 (0x189E)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : 129
Duration : 35mn 58s
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
Delay relative to video : -562ms
Stream size : 98.8 MiB (2%)
Language : English
}}}
I use mythtranscode from the CLI, and created the transcoded video thusly:
{{{
mythtranscode --chanid 1577 --starttime 20160327135900 --mpeg2
--honorcutlist -e ts --passthrough -o ~/tmp/myrecording.mpg
}}}
The audio of the resultant file (mediainfo):
{{{
Audio #1
ID : 4301 (0x10CD)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : 129
Duration : 24mn 29s
Bit rate mode : Constant
Bit rate : 192 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Delay relative to video : 8ms
Stream size : 33.6 MiB (1%)
Language : English
}}}
Note the Channel(s) are reduced from 6 to 2, and the 'Bit rate' reduced to
192Bkps from 384Kbps.
This is, however, incorrect. Playing the transcoded file with VLC shows:
{{{
Type: Audio
Original ID: 4301
Codec: A52 Audio (aka AC3)(a52 )
Language: Englisg
Channels: 3F2R/LFE
Sample rate: 48000 Hz
Bitrate: 384 kb/s
}}}
Note that it IS actually 6 channel, 384Kbps. So the audio of the file is
correct, but the descriptors in the TS container are incorrect.
Unfortunately, when I open the transcoded file with HandBrake, HandBrake
reports that the source audio is only 2 channel, and therefore cannot
transcode to, e.g. AAC 6 channel; only 2.
--
Ticket URL: <https://code.mythtv.org/trac/ticket/12728>
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