[FFmpeg-devel] [FFmpeg-cvslog] fftools/ffmpeg_filter: fix the flags parsing for scaler

[Michael Niedermayer]

On Thu, Aug 05, 2021 at 02:30:32PM +0000, Linjie Fu wrote:
> ffmpeg | branch: master | Linjie Fu <linjie.justin.fu at gmail.com> | Sun Aug  1 18:58:19 2021 +0800| [b3a0548a981db52911dd34d9de254c4fee0a8f79] | committer: Linjie Fu
> 
> fftools/ffmpeg_filter: fix the flags parsing for scaler
> 
> Scaler relys on "-sws_flags" option to pass the flags to swscale
> and scale filter. Currently passing "sws_flags=xxx" as a filter
> option to scaler leads to an incorrect option parsing.
> 
> Check and change the string to "flags=xxx" and dumped flags information.
> (Refer to parse_sws_flags())
> 
> CMD:
> $ffmpeg -v verbose -i input.mp4 -sws_flags lanczos+bitexact+accurate_rnd \
>         -vf format=yuv420p,scale=800x600 -an -vframes 10 -f md5 -
> 
> Before:
> [auto_scaler_0 @ 0x7f96c3808680] w:iw h:ih flags:'' interl:0
> [auto_scaler_0 @ 0x7f96c3808680] w:1920 h:1080 fmt:yuvj420p sar:0/1 -> w:1920 h:1080 fmt:yuv420p sar:0/1 flags:0x0
> [Parsed_scale_1 @ 0x7f96c3806e40] w:1920 h:1080 fmt:yuv420p sar:0/1 -> w:800 h:600 fmt:yuv420p sar:0/1 flags:0x0
> MD5=ff1d6091690c6fcd36d458d2a9f648ce
> 
> After:
> [auto_scaler_0 @ 0x7fe94563b4c0] w:iw h:ih flags:'lanczos+bitexact+accurate_rnd' interl:0
> [auto_scaler_0 @ 0x7fe94563b4c0] w:1920 h:1080 fmt:yuvj420p sar:0/1 -> w:1920 h:1080 fmt:yuv420p sar:0/1 flags:0xc0200
> [Parsed_scale_1 @ 0x7fe945639d00] w:1920 h:1080 fmt:yuv420p sar:0/1 -> w:800 h:600 fmt:yuv420p sar:0/1 flags:0xc0200
> MD5=ff1d6091690c6fcd36d458d2a9f648ce
> 
> Signed-off-by: Linjie Fu <linjie.justin.fu at gmail.com>
> 
> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b3a0548a981db52911dd34d9de254c4fee0a8f79
> ---

This breaks
-i laraShadow_dl.flv  -alphablend checkerboard -qscale 2 -t 0.5 file.avi

After this commit the output is just black

sample seems here:
https://samples.ffmpeg.org/FLV/flash_with_alpha/


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Dictatorship: All citizens are under surveillance, all their steps and
actions recorded, for the politicians to enforce control.
Democracy: All politicians are under surveillance, all their steps and
actions recorded, for the citizens to enforce control.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20210806/1b94dba8/attachment.sig>