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IDProjectCategoryView StatusDate SubmittedLast Update
0000305Cinelerra-GG[All Projects] Bugpublic2019-09-20 19:122019-10-02 00:43
Reporterkex Assigned Togoodguy  
PrioritynormalSeveritymajorReproducibilityalways
Status closedResolutionfixed 
Product Version 
Target VersionFixed in Version2019-09 
Summary0000305: VP9 presets and some others are possibly wrongly setting ffmpeg bitrate
DescriptionI was trying to use libvpx to encode my video with 'crf' mode but it always produced low-bitrate, low quality output.

For my CRF setup, it is necessary to set bitrate to 0 but Cinelerra won't set bitrate ffmpeg codec option if the Bitrate field is 0 (to allow setting quality). Keeping defaults Bitrate 0 and Quality -1 makes Cinelerra skip setting bitrate or quality (probably keeping some low ffmpeg default). So custom ffmpeg parameters have to be set.

The problem is, setting 'bitrate=0' doesn't work while setting 'b=0' does!
Therefore I suspect that other presets in '/usr/share/cinelerra-gg/ffmpeg/' setting 'bitrate=' instead of 'b=' may be wrong.

For VP9 CRF, minrate and maxrate may be used together with crf to constrain the resulting bitrate in the output file.
Steps To ReproduceUse stock vp9_1920x1080_24or25or30fps.webm preset packaged with Cinelerra which contains:
webm libvpx-vp9
# 20171119-2100
# based on https://developers.google.com/media/vp9/settings/vod/
# for explanations see Feature5.pdf section 3
# 1920x1080 (24, 25 or 30 frames per second)
bitrate=1800k
minrate=900k
maxrate=2610k
tile-columns=2
g=240
threads=8
quality=good
crf=31
speed=4


That results in low quality output.
Additional InformationChange bitrate=0 to b=0 to fix the problem:
webm libvpx-vp9
# 20171119-2100
# based on https://developers.google.com/media/vp9/settings/vod/
# for explanations see Feature5.pdf section 3
# 1920x1080 (24, 25 or 30 frames per second)
b=0
minrate=900k
maxrate=2610k
tile-columns=2
g=240
threads=8
quality=good
crf=31
speed=4
TagsNo tags attached.

Activities

PhyllisSmith

PhyllisSmith

2019-09-23 00:27

manager   ~0002170

OOPS! not sure how we missed this, but THANKS for letting us know so we could fix it.
   bitrate=# has now been changed to b=# in 30 of the ffmpeg video opts files, checked into GIT, and will be in new builds.

BTW: if you have a specific set of parameter values that you use on a frequent basis and would like to include this in the video opts directory, just provide a descriptive name along with the parameters and we will include it in the Cinelerra distribution.
PhyllisSmith

PhyllisSmith

2019-09-21 17:24

manager   ~0002163

Just wanted to acknowledge this issue so you know we saw it. I will have to delve into the details before I can respond intelligently! but sometimes the parameters needed by ffmpeg are passed a little differently from within Cin.

Issue History

Date Modified Username Field Change
2019-09-20 19:12 kex New Issue
2019-09-21 17:24 PhyllisSmith Assigned To => PhyllisSmith
2019-09-21 17:24 PhyllisSmith Status new => acknowledged
2019-09-21 17:24 PhyllisSmith Note Added: 0002163
2019-09-23 00:27 PhyllisSmith Status acknowledged => confirmed
2019-09-23 00:27 PhyllisSmith Note Added: 0002170
2019-10-01 01:51 PhyllisSmith Assigned To PhyllisSmith => goodguy
2019-10-01 01:51 PhyllisSmith Status confirmed => resolved
2019-10-01 01:51 PhyllisSmith Resolution open => fixed
2019-10-01 01:51 PhyllisSmith Fixed in Version => 2019-09
2019-10-02 00:43 PhyllisSmith Status resolved => closed