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shshankjain / webm

Automatically exported from code.google.com/p/webm
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Rate control discontinuities at high bitrates (~35Mbps) #173

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Rate control seems to go haywire around 35Mbps, suspect integer overflow. This 
appears to be irrespective of resolution. Tested for 1080p:

$ for b in 30000 40000; do ./ivfenc --target-bitrate=$b ~/g/video/sunflower.y4m 
/dev/null; done
Pass 1/1 frame  500/500  59862220B  957795b/f 23944888b/s  496350 ms (1.01 fps)
Pass 1/1 frame  500/500  27788039B  444608b/f 11115215b/s  390115 ms (1.28 fps)

Also see attached graph (from akiyo_cif.y4m), and this thread: 
http://groups.google.com/a/webmproject.org/group/webm-discuss/browse_thread/thre
ad/1ccb1436b1307fed#

Original issue reported on code.google.com by jkoles...@google.com on 8 Sep 2010 at 3:19

Attachments:

GoogleCodeExporter commented 9 years ago 
Confirmed that this issue is still present in v0.9.6-57-g71bcd9f, though note 
that the 30Mbps data point is much closer now.

$ for b in 30000 40000; do ./vpxenc -o /dev/null --target-bitrate=$b 
~/g/video/sunflower.y4m ; done
Pass 1/1 frame  500/500  81304624B 1300873b/f 32521849b/s  499434 ms (1.00 fps)
Pass 1/1 frame  500/500  31088185B  497410b/f 12435274b/s  315446 ms (1.59 fps)

Original comment by jkoles...@google.com on 17 Mar 2011 at 7:12

GoogleCodeExporter commented 9 years ago

Original comment by albe...@google.com on 8 Mar 2012 at 12:05

GoogleCodeExporter commented 9 years ago 
Jim will look at it.

Original comment by albe...@google.com on 15 Mar 2012 at 6:17

GoogleCodeExporter commented 9 years ago 
With Tip I ran the following changes and while I can apparently hit 30 megabit 
only by requesting 40 megabit I no longer see the weird bitrate drop offs you 
reported. 

for b in 30000 40000; do vpxenc -o s$b.webm --target-bitrate=$b _sunflower.y4m 
; done
Pass 1/1 frame  500/500  21325257B  341204b/f 8530102b/s  577631 ms (0.87 fps)
Pass 1/1 frame  500/500  34182611B  546921b/f 13673044b/s  592660 ms (0.84 fps)
for b in 50000 60000; do vpxenc -o s$b.webm --target-bitrate=$b _sunflower.y4m 
; done
Pass 1/1 frame  500/500  37698956B  603183b/f 15079582b/s  571810 ms (0.87 fps)
Pass 1/1 frame  500/500  37743622B  603897b/f 15097448b/s  573399 ms (0.87 fps)

Can you please download tip and give it a try?

Original comment by jimbankoski@google.com on 3 Apr 2012 at 12:33

GoogleCodeExporter commented 9 years ago 
There might be another issue but original bug (discontinuity is fixed)

Original comment by albe...@google.com on 12 Apr 2012 at 6:04