[FFmpeg-trac] #7600(avcodec:reopened): Add lossless option to libaom-av1

FFmpeg trac at avcodec.org
Sat Mar 20 19:12:58 EET 2021


#7600: Add lossless option to libaom-av1
-------------------------------------+------------------------------------
             Reporter:  Ewout        |                    Owner:
                 Type:  enhancement  |                   Status:  reopened
             Priority:  wish         |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  libaom       |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+------------------------------------
Changes (by Balling):

 * status:  closed => reopened
 * resolution:  invalid =>


Comment:

 Replying to [comment:13 cehoyos]:
 > I can confirm that lossless encoding works fine with `-crf 0`.

 You are wrong. It is not lossless.

 While latest aoemenc from here is lossless even for 4:2:0:
 https://ci.appveyor.com/project/marcomsousa/build-
 aom/builds/38315239/artifacts did get inf SSIM and PSNR. I hope you can
 fix this ASAP.

 {{{
 [Parsed_ssim_0 @ 00000123da0a7280] SSIM Y:1.000000 (inf) U:1.000000 (inf)
 V:1.000000 (inf) All:1.000000 (inf)
 [Parsed_psnr_1 @ 00000123da0a8140] PSNR y:inf u:inf v:inf average:inf
 min:inf max:inf

 }}}

 Maybe you tested 4:4:4? Or something.

 I used aomenc.exe --lossless=1 -o output.webm source1.y4m

 It will/can create VFR file, so be accurate and get back to y4m. It can
 also add some DTS warnings!


 {{{
 [null @ 000001a3eab6b7c0] Application provided invalid, non monotonically
 increasing dts to muxer in stream 0: 89 >= 89
 [null @ 000001a3eab6b7c0] Application provided invalid, non monotonically
 increasing dts to muxer in stream 1: 89 >= 89

 }}}

 And you MUST be very careful, because for high bitrate AV1 can be lossless
 in BY ITSELF!

 https://www.reddit.com/r/AV1/comments/aylb98/aomenc_near_lossless_encoding/

 Also aomenc was not lossless some time ago, that also should be checked.
 https://www.texpion.com/2018/07/av1-vs-vp9-vs-avc-h264-vs-
 hevc-h265-1-lossless.html

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7600#comment:14>
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