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

FFmpeg trac at avcodec.org
Sun Mar 21 00:43:21 EET 2021

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

Comment (by pdr0):

 Replying to [comment:26 Balling]:
 > Replying to [comment:25 pdr0]:
 > > That issue is fixed when using  -c:v libaom-av1 -aom-params lossless=1
 > >
 > > I participated in that thread and revisited it just now
 > >
 > > I also tested a few different samples (patterns, and real), 8bit and
 10bit, all more than 8frames,  and all were lossless with the -aom-params
 lossless=1 switch. Confirmed "lossless" using ffmpeg psnr, and using
 methods outside of ffmpeg
 > >
 > > Do you have a test source that is "not lossless" with -aom-params
 lossless=1 (1st frame or not) ?
 > Yes, -aom-params lossless=1 works for me after all. Thanks to
 > {{{
 > -framemd5 -
 > }}}
 >  as it is much more effective here...
 > How can you be sure that lossless=1 actually '''GOT''' applied? -v debug
 does not show any difference, as there is no AV1E_SET_LOSSLESS! Also, it
 will force -cfr 32, the default value (but is still lossless)...
 > And of course no ENCODER_SETTINGS metadata. :(

 ffmpeg report does not say lossless switch applied (only read)... but
 aomenc.exe does not display that info either with --verbose, nor does
 aomenc.exe output stream have metadata (yet). If/when it gets implemented
 in aomenc, then you should see it in ffmpeg libaom-av1

Ticket URL: <https://trac.ffmpeg.org/ticket/7600#comment:27>
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