[mythtv-commits] Ticket #4819: Faint audio from 5.1 upmix on MPEG-4 files
MythTV
mythtv at cvs.mythtv.org
Mon Mar 3 04:52:54 UTC 2008
#4819: Faint audio from 5.1 upmix on MPEG-4 files
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Reporter: Yeechang Lee <ylee at pobox.com> | Owner: ijr
Type: defect | Status: new
Priority: minor | Milestone: unknown
Component: mythtv | Version: head
Severity: medium | Mlocked: 0
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I am running r16254, and have noticed this issue since the multichannel
audio support in #1104 was committed to trunk. Relevant ./configure flags
are --enable-libx264, --enable-libmp3lame, --enable-libfaad, --enable-
libfaac, --enable-libfftw3.
My frontend outputs audio via S/PDIF. I have AC3 and DTS passthrough
enabled. My Myth recordings are all originally in MPEG-2 (via OTA or
FireWire); many have AC3 tracks. Some recordings have since been converted
by mythtranscode into MPEG-4, which also downmixed any AC3 tracks into
stereo. I also play via MythVideo various AVI files in both Xvid and Divx
formats with either AC3 or MP3 audio.
If I set Max Audio Channels to 5.1 and Upmix to either Active Linear or
Active Simple, here is what I get audiowise with various video/audio
combinations, with no timestretch used:
* MPEG-2/AC3: No problem.
* MPEG-2/non-AC3: No problem.
* MPEG-4/non-AC3: Audio is so faint it's almost inaudible.
* Xvid/MP3: Audio is so faint it's almost inaudible.
* Divx/AC3: No problem.
The audio problems go away if I either set Max Audio Channels to Stereo,
or keep Max Audio Channels at 5.1 but set Upmix to Passive.
Brad Dermanouelian [http://www.gossamer-
threads.com/lists/mythtv/users/319415#319415 reports the same issue] with
his analog card-captured MPEG-4 MythTV recordings.
--
Ticket URL: <http://svn.mythtv.org/trac/ticket/4819>
MythTV <http://svn.mythtv.org/trac>
MythTV
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