Opened 16 years ago
Closed 15 years ago
#4819 closed defect (duplicate)
Faint audio from 5.1 upmix on MPEG-4 files
| Reported by: | Owned by: | danielk | |
|---|---|---|---|
| Priority: | minor | Milestone: | unknown |
| Component: | mythtv | Version: | head |
| Severity: | medium | Keywords: | mpeg-4 xvid divx upmix multichannel audio stereo active linear simple passive 5.1 |
| Cc: | Ticket locked: | no |
Description
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 reports the same issue with his analog card-captured MPEG-4 MythTV recordings.
Change History (6)
comment:1 Changed 16 years ago by
comment:2 Changed 16 years ago by
| Owner: | changed from Isaac Richards to danielk |
|---|---|
| Status: | new → assigned |
Does this still happen when ./configure is run with no options?
comment:3 Changed 16 years ago by
Daniel - have not tested with just ./configure. Here were my configure options:
./configure --enable-proc-opt --disable-xvmcw --enable-xvmc-opengl --enable-o
pengl-video --enable-opengl-vsync --enable-libfftw3 --xvmc-lib=XvMCNVIDIA
Also - I need to clarify my last comment above - It was MPEG4 video with MP2 audio. I can submit a sample off-list if needed.
comment:4 Changed 16 years ago by
I also explained my issues, which match up with those described in the ticket, in this thread: http://www.gossamer-threads.com/lists/mythtv/users/321375#321375
I'm also getting this with some MPEG2 videos with MP3 audio (not recordings). Barely Audible sound, also sounds washed out.