Opened 10 years ago
Closed 9 years ago
#4025 closed defect (invalid)
Encoding speed of webm vp8 has declined signficantly
Reported by: | Scott Dowdle | Owned by: | |
---|---|---|---|
Priority: | minor | Component: | documentation |
Version: | git-master | Keywords: | libvpx |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description
Summary of the bug: Encoding speed for webm (vp8/theora) with ffmpeg 2.1.5 was significantly faster than it is now in ffmpeg 2.3.4
How to reproduce:
I primarily use the ffmpeg packages provided by rpmfusion for Fedora. In Fedora 20 the ffmpeg version available through rpmfusion is 2.1.5. I recently installed Fedora 21 pre-beta and rpmfusion rawhide has ffmpeg 2.3.4. The encoding speed for webm (vp8/theora) videos is significantly different between the versions.
I also tried a static build of the contemporary release (ffmpeg-2.4.2-64bit-static.tar.xz) and discovered that it too is very slow when encoding webm (vp8/theora) videos.
In a related note, webm (vp9/opus) works much better in newer releases and I wanted to try that out as well... but I have to wonder if the addition of vp9/opus code has slowed down the encoding speed for vp8/theora?
Both Fedora 20 and 21 pre-beta are using libvpx-1.3.0.
Command lines given:
ffmpeg -y -i source.mp4 -f webm -b:v 800k -b:a 96k -ac 2 -sn output.webm
On a Dell Optiplex 9010 with an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, I was getting about 80 FPS encoding with ffmpeg 2.1.5 but now with ffmpeg 2.3.4, I'm gettin about 20 FPS.
Change History (7)
comment:1 by , 10 years ago
Component: | undetermined → documentation |
---|---|
Keywords: | vpx added |
Priority: | normal → minor |
Status: | new → open |
follow-up: 3 comment:2 by , 10 years ago
Keywords: | libvpx added; vpx removed |
---|---|
Version: | unspecified → git-master |
I still wonder how this ticket is related to theora...
comment:3 by , 10 years ago
Summary: | Encoding speed of webm (vp8/theora) has declined signficantly → Encoding speed of webm vp8 has declined signficantly |
---|
Replying to cehoyos:
I still wonder how this ticket is related to theora...
It isn't. dowdle most likely meant to say vorbis.
comment:4 by , 10 years ago
Yes, I confused the two. Sorry.
So, can anyone confirm the significant reduction in encoding speeds? It is very consistent for me on multiple machines with the same source material.
comment:5 by , 10 years ago
You can confirm it yourself, just follow the link above: The default was changed to higher quality / slower speed, just increase the speed with -speed 3
to get the old behaviour (that was not documented afaict).
comment:7 by , 9 years ago
Resolution: | → invalid |
---|---|
Status: | open → closed |
Looking at the history of libvpxenc.c, it seems the one of the default settings was changed starting with ffmpeg 2.2, commit 34e32d6464135a03da14d5b0aef1d42796939eae (Changing the speed/cpu-used setting from 3 to 1).
If you use the default settings (Like you're doing with the command line example you gave above) then it will of course be slower now since we default to a slower but higher quality encoding setting.
For an approximation of the old behavior back try running something like "ffmpeg -y -i source.mp4 -f webm -cpu-used 3 -b:v 800k -b:a 96k -ac 2 -sn output.webm".