target-bitrate seems to be ignored

[GoogleCodeExporter]

I am setting cbr and target-bitrate , but the actual bitrate rises way over the 
selected bitrate. it seems that the only parameter affecting the actual bitrate 
is max-q , but if I set max-q to 40 then the bitrate is high when there is 
allot of image changes ( much more then target-bitrate ) and if I set it to 63 
it is always low bitrate ( less then target-bitrate ) even when there are allot 
of image changes.

I am using v1.3.0 on android arm

Original issue reported on code.google.com by jacobham...@gmail.com on 3 Nov 2014 at 9:48

[GoogleCodeExporter]

Do you still see this when using the latest from git? vp8 or vp9? Depending on 
your use case it may be worth checking out the WebRTC settings:
https://code.google.com/p/webrtc/source/browse/trunk/webrtc/modules/video_coding
/codecs/vp8/vp8_impl.cc

Original comment by johannko...@google.com on 3 Nov 2014 at 5:14

• Changed state: Unconfirmed

[GoogleCodeExporter]

Original comment by johannko...@google.com on 6 Nov 2014 at 12:52

• Added labels: Hotlist-IndianRunnerDuck

[GoogleCodeExporter]

Gentle ping on this bug. Thanks.

Original comment by renganat...@google.com on 20 Nov 2014 at 11:17

• Changed state: Assigned

[GoogleCodeExporter]

Insufficient information.

Original comment by johannko...@google.com on 15 Jan 2015 at 8:13

• Changed state: WontFix

[GoogleCodeExporter]

This is still an issue on master - ccffe318ffc90ae584c33e254b3a35e9142ecc20  ( 
vp8 ), please tell me what kind of additional  information do you need ?

Original comment by jacobham...@gmail.com on 3 Mar 2015 at 10:30

[GoogleCodeExporter]

What kind of source material? What bitrates are you targeting and what are the 
rates you're getting? What other settings are you using? Did you try the WebRTC 
settings?

Original comment by johannko...@google.com on 3 Mar 2015 at 10:38

[GoogleCodeExporter]

I am not quite sure what do you mean by source material.
I am using gstreamer master vp8enc plugin it uses libvpx master ( commit - 
ccffe318ffc90ae584c33e254b3a35e9142ecc20 ), I am targeting 150kbit/s , when the 
content is static I get low bitrates ~50kbit/s but when the content changes 
allot I get up to ~400kbit/s ( and it stays high until content static again ). 
I have tried many different settings ( also from webrtc code ) here is an 
example:

--cpu-used=6 --deadline=1 --rt --end-usage=cbr --target-bitrate=150 
--kf-max-dist=999999 --undershoot-pct=0 --overshoot-pct=0 --buf-sz=1000 
--buf-initial-sz=500 --buf-optimal-sz=600

Original comment by jacobham...@gmail.com on 4 Mar 2015 at 7:42

[GoogleCodeExporter]

The source material is the input that you are encoding. Movie, screencasting, 
talking head, etc. If you have a copy of the raw input as y4m it makes testing 
much easier.

What resolution are you targeting? 50kbit/s seems very low. Have you tried 
--drop-frames?

Marco - do you have any ideas about expected/reasonable bitrates for static 
content/talking heads?

Original comment by johannko...@google.com on 5 Mar 2015 at 12:41

• Changed state: Unconfirmed

[GoogleCodeExporter]

The source material is android screencasting therefore the actual source is 
what is running on the tablet, which can be static ( mostly ) or talking head 
or movie etc. 

this is a sample y4m file (1280x800 12fps) :
https://www.dropbox.com/s/pt2tum78p6mv6o9/cap4.zip?dl=0

I am targeting 1280x800 and I need to be able to capture the screen, in some 
cases as low as 150kbit/s . I tried --drop-frames but that results in a jumpy 
and very low frame rate output. 
It would be best for me if I can set the rate to a CBR of 150kbit/s and when 
source is static I get higher quality output and when there is allot of 
movement lower quality, but the bitrate would stay the same...

This kind of use case works currently very well with x264 but I would like to 
move to libvpx.

Original comment by jacobham...@gmail.com on 8 Mar 2015 at 9:48

[GoogleCodeExporter]

Original comment by fgalli...@google.com on 12 Mar 2015 at 10:20

• Changed state: Assigned