> -----Original Message----- > From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of > Scott Theisen > Sent: Thursday, February 3, 2022 11:17 PM > To: ffmpeg-devel@ffmpeg.org > Subject: Re: [FFmpeg-devel] [PATCH] avcodec/dvdsubdec: fix incorrect > yellow appearance of dvd subtitles > > On 2/3/22 17:10, Soft Works wrote: > > > >> -----Original Message----- > >> From: ffmpegagent <ffmpegag...@gmail.com> > >> Sent: Tuesday, January 4, 2022 3:19 AM > >> To: ffmpeg-devel@ffmpeg.org > >> Cc: softworkz <softwo...@hotmail.com>; softworkz > >> <softwo...@hotmail.com> > >> Subject: [PATCH] avcodec/dvdsubdec: fix incorrect yellow appearance > of > >> dvd subtitles > >> > >> From: softworkz <softwo...@hotmail.com> > >> > >> The guess_palette() implementation is questionable in itself > >> as its results don't match those from other DVD subtitle decoders. > >> > >> This commit starts cleanup by fixing an obvious bug which has made > >> certain DVD subs appear yellow instead of white or grey for more > than > >> 10 years.. > >> > >> Signed-off-by: softworkz <softwo...@hotmail.com> > >> --- > >> avcodec/dvdsubdec: fix incorrect yellow appearance of dvd > >> subtitles > >> > >> Fixes an age-old bug in decoding DVD subtitles. > >> > >> Ever wondered why certain DVD subtitles are shown in yellow > color > >> when > >> ffmpeg is involved... > >> > >> Published-As: https://github.com/ffstaging/FFmpeg/releases/tag/pr- > >> ffstaging-16%2Fsoftworkz%2Fpatch_dvdsubdec_fix-v1 > >> Fetch-It-Via: git fetch https://github.com/ffstaging/FFmpeg pr- > >> ffstaging-16/softworkz/patch_dvdsubdec_fix-v1 > >> Pull-Request: https://github.com/ffstaging/FFmpeg/pull/16 > >> > >> libavcodec/dvdsubdec.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/libavcodec/dvdsubdec.c b/libavcodec/dvdsubdec.c > >> index 52259f0730..a3fdb535a5 100644 > >> --- a/libavcodec/dvdsubdec.c > >> +++ b/libavcodec/dvdsubdec.c > >> @@ -400,7 +400,7 @@ static int decode_dvd_subtitles(DVDSubContext > >> *ctx, AVSubtitle *sub_header, > >> } else { > >> sub_header->rects[0]->nb_colors = 4; > >> guess_palette(ctx, (uint32_t*)sub_header- > >>> rects[0]->data[1], > >> - 0xffff00); > >> + 0xffffff); > >> } > >> sub_header->rects[0]->x = x1; > >> sub_header->rects[0]->y = y1; > >> > >> base-commit: 573b6b8a607398c5f34108efda9c29d41c5727ff > >> -- > >> ffmpeg-codebot > > Ping. (no maintainer seems to be registered for this) > > MythTV has used this fix since 2010-06-04. See > https://github.com/ulmus- > scott/FFmpeg/commit/e2b1a6ee63c0cccc1ac9c82d24e2e6cfffeb2bfc > > libavcodec/dvdsubdec.c: default to white instead of yellow > > from Improved display of DVD subtitles in containers other than the > original. > https://github.com/MythTV/mythtv/commit/2510a0821ea4453eb9b34dd96e68ff > 0441459d0b > references: https://code.mythtv.org/trac/ticket/8222
Thanks for the references. I have compared the ffmpeg output with a range of (non-ffmpeg-based) players including VLC, an example where I had a screen photo from a hardware player and two subtitle editing tools. None of those showed them yellow. > For whatever strange reason, ffmpeg has always used yellow: > https://github.com/FFmpeg/FFmpeg/commit/240c1657dcd45adc0e63ef947b9209 > 19071ec1f7 My suspicion is that 0xffff00 was written assuming RGBA order instead of ARGB. I'm pretty sure that it's a mistake and it hasn't been an intentional choice, because even when you would consider a yellow color to for whatever reason, it wouldn't have been exactly this yellow (#ff0), because its lightness/saturation values are not in a range of what is suitable for colored subtitles. softworkz _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
