Opened 2 months ago

Closed 5 days ago

Last modified 5 days ago

#7488 closed defect (invalid)

CRF value not working when encoding with libaom in AV1 (2)

Reported by: Ewout Owned by:
Priority: normal Component: undetermined
Version: git-master Keywords: libaom
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no

Description

Excuse me for reporting inconclusive data in my first ticket (#7483).

Summary of the bug: CRF value not working when encoding with libaom in AV1
How to reproduce:

ffmpeg -i C:\Morocco8khdr60fps-1280.m4v -c:v libaom-av1 -crf 6 -strict experimental av1_test_Morocco8K_1280crf6.mkv
ffmpeg -i C:\Morocco8khdr60fps-1280.m4v -c:v libaom-av1 -crf 12 -strict experimental av1_test_Morocco8K_1280crf12.mkv
ffmpeg -i C:\Morocco8khdr60fps-1280.m4v -c:v libaom-av1 -crf 18 -strict experimental av1_test_Morocco8K_1280crf18.mkv
ffmpeg -i C:\Morocco8khdr60fps-1280.m4v -c:v libaom-av1 -crf 24 -strict experimental av1_test_Morocco8K_1280crf24.mkv

ffmpeg version: ffmpeg-20181007-0a41a8b-win64-static
built on: Windows 10 64-bit (1809)

I encoded a high-bitrate m4v file (encoded with x264) to AV1 with different CRF values. All came out with the same bitrates. See the attached screenshots. Files can be found here: https://drive.google.com/file/d/1e4QmCXavsJqxzI4OOS5jqfMmSSmGPD4B/view?usp=sharing

The input file was 16 MB, around 1 MB/s. With CRF values of 6, 12, 18 and 24 they all encoded to the same 836 kB (855.592 bytes), around 52 kB/s.

Attachments (2)

Screenshot_332.png (228.4 KB) - added by Ewout 2 months ago.
Encode settings
Screenshot_331.png (232.0 KB) - added by Ewout 2 months ago.
Encode results

Download all attachments as: .zip

Change History (6)

Changed 2 months ago by Ewout

Encode settings

Changed 2 months ago by Ewout

Encode results

comment:1 Changed 2 months ago by cehoyos

  • Keywords av1 crf removed
  • Version changed from unspecified to git-master

Why do you believe this is an issue that can be fixed in FFmpeg?

comment:2 Changed 6 weeks ago by Ewout

jamrial updated the AV1 encode wiki by adding that -b:v needs to be specified, where -b:v 0 gives a constant quality and -b:v int gives a constant quality with max bit-rate int.

I will test today if this fixes the issue.

Last edited 6 weeks ago by Ewout (previous) (diff)

comment:3 Changed 5 days ago by Ewout

  • Resolution set to fixed
  • Status changed from new to closed

comment:4 Changed 5 days ago by cehoyos

  • Resolution changed from fixed to invalid
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