Ticket #4653 (closed enhancement: fixed)
Opened 4 years ago
Last modified 2 years ago
Allow Enable/Disable of deblocking loopfilter for h.264 ffmpeg (BBC HD support)
| Reported by: | reidjr_at_lineone_net | Owned by: | jyavenard |
|---|---|---|---|
| Priority: | minor | Milestone: | 0.24 |
| Component: | MythTV - Video Playback | Version: | head |
| Severity: | medium | Keywords: | h.264 skip loop filter BBC HD |
| Cc: | stuartm | Ticket locked: | yes |
Description
Adds a selct box in the videoprofile settings that will enable/disable the de-blocking loopfilter for h.264 ffmpeg. Disabling the deblocking loop filter makes a significant diffrence to cpu load for h.264 decoding. When used with both CPU's of a core2duo e4300, disabling the loopfilter will allow playing back BBC HD at 60-70% of both cores. With th eloopfilter active (current default) then frames are dropped. As the setting is part of the videoprofile, it can selectively be used for HD.
Attachments
Change History
Changed 4 years ago by reidjr_at_lineone_net
- Attachment skip_loopfilter_settings.diff added
comment:1 Changed 4 years ago by janne
- Owner changed from ijr to janne
- Status changed from new to assigned
- Milestone changed from unknown to 0.22
I'll work on a general way of setting avcodec options
Changed 4 years ago by robert.mcnamara@…
- Attachment skiplooppatch_16446.diff.txt added
Patch updated to work with 16446 for anyone interested
comment:3 Changed 4 years ago by stuartm
- Owner changed from janne to stuartm
- Version changed from unknown to head
comment:4 Changed 4 years ago by janne
- Owner changed from stuartm to janne
- Status changed from assigned to started
Changed 4 years ago by laga@…
- Attachment 25_skiploop_option.dpatch added
Updated the patch to work if you only have one playback thread. Thanks to janneg for pointing this out
comment:5 Changed 3 years ago by janne
- Status changed from started to accepted
- Milestone changed from 0.22 to 0.23
deprecated started state
comment:6 follow-up: ↓ 7 Changed 3 years ago by reidjr_at_lineone_net
I've updated the patch for trunk, as it looks like it will miss another release. I have also added a really minimalist patch. which just hard codes the loopfilter off.
There is a strange thing I am seing though. Without the patch, multithreading h264 doesnt work, whatever you set max CPUs to. With the patch Setting the loopfilter option to off, doesnt save any overall cpu load, but does allow multithreading to work. Looks like either ffmpeg or underlying code has changed.
I would suggest only applying this patch if you have multi-core cpu.
comment:7 in reply to: ↑ 6 Changed 3 years ago by janne
Replying to reidjr_at_lineone_net:
There is a strange thing I am seing though. Without the patch, multithreading h264 doesnt work, whatever you set max CPUs to. With the patch Setting the loopfilter option to off, doesnt save any overall cpu load, but does allow multithreading to work. Looks like either ffmpeg or underlying code has changed.
The deblocking loop filter can prevent the slice paralell decoding. It's a known limitation of ffmpeg's slice level multithreaded decoding.
comment:8 Changed 3 years ago by reidjr_at_lineone_net
Ok, as multi cpu / thread decoding doesnt work with loop filter enabled, a really trivial patch for those in the UK that need it. Sett max CPUs to more than 1 and the loop filter is disabled, and multiple threading is enabled for BBC-HD, and although ITV-HD stays single threaded, the cpu load is reduced.
Changed 3 years ago by reidjr_at_lineone_net
- Attachment 28_skiploop_multithread.dpatch added
as described above
Changed 3 years ago by jyavenard
- Attachment 29_skiploop_trunk_22847.2.diff added
Updated for trunk r22847
Changed 3 years ago by jyavenard
- Attachment 29_skiploop_fixes_022.diff added
Updated for 0.22-fixes r22847
comment:10 Changed 3 years ago by jyavenard
Updated for 0.22-fixes and trunk
comment:11 Changed 2 years ago by helge.jensen@…
This is a welcome tradeoff for me. I would rather see my HD-content in slightly reduced quality than jittering at ~46fps (or 0.9x which also works for me :)
The patch is pretty small, how come it has not been included yet? 2 (two) years down the line.
comment:13 Changed 2 years ago by robertm
- Milestone changed from 0.23 to 0.24
Pushing to .24 since we're in freeze.
comment:14 Changed 2 years ago by jyavenard
- Owner changed from janne to jyavenard
- Status changed from accepted to assigned
comment:15 Changed 2 years ago by jyavenard
- Status changed from assigned to closed
- Resolution set to fixed
Fixed in r23981
Add ability to disable the deblocking skiploop filter for h264 decoding. This will speedup h264 decoding, but may drastically reduce quality. Original patch from reidjr_at_lineone_net with various other contributors. Thank you all
Reduce CPU load h.264 ffmpeg decoding.