Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
On Fri, 8 May 2015 10:30:34 + (UTC) Carl Eugen Hoyos ceho...@ag.or.at wrote: wm4 nfxjfg at googlemail.com writes: I believe this is slightly misleading: gray8 and gray16 are interpreted as full-range by default since years. Really? Where? In the software scaler. Doesn't matter much from the API user point of view. Not everyone uses libswscale. As said, I had no objections against your patch (on the contrary) but I wonder why you want to set a field that is mostly useful when using libswscale if you don't use libswscale. Uh, what? Do you think libswscale is the only thing that processes video? There is the (unwritten?) convention that YUV is limited range, and RGB is full range. GRAY is somewhat both, but at least the pixdesc tables do not mark it as RGB. I don't think the issue is related to (current) pixdesc but I may miss something. What is your opinion about this? I committed part of the change making gray full range... Whoever wants to use frame-data[0] should use it;-) What do you even mean? So what is the API user supposed to do? Special-case by codec? Just what is it? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
wm4 nfxjfg at googlemail.com writes: I believe this is slightly misleading: gray8 and gray16 are interpreted as full-range by default since years. Really? Where? In the software scaler. Doesn't matter much from the API user point of view. Not everyone uses libswscale. As said, I had no objections against your patch (on the contrary) but I wonder why you want to set a field that is mostly useful when using libswscale if you don't use libswscale. There is the (unwritten?) convention that YUV is limited range, and RGB is full range. GRAY is somewhat both, but at least the pixdesc tables do not mark it as RGB. I don't think the issue is related to (current) pixdesc but I may miss something. What is your opinion about this? I committed part of the change making gray full range... Whoever wants to use frame-data[0] should use it;-) Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
On Fri, 8 May 2015 11:29:18 + (UTC) Carl Eugen Hoyos ceho...@ag.or.at wrote: wm4 nfxjfg at googlemail.com writes: As said, I had no objections against your patch (on the contrary) but I wonder why you want to set a field that is mostly useful when using libswscale if you don't use libswscale. Uh, what? Do you think libswscale is the only thing that processes video? No, but it seemed to me that this is what your commit message implied. What is your opinion about this? I committed part of the change making gray full range... Whoever wants to use frame-data[0] should use it What do you even mean? I thought your question was Do you agree that gray should be full-range? Some people need the yuv - In what context? Yes, png outputs full range gray, but that doesn't mean other codecs outputting gray do this. gray conversion not to change the values, and I always wonder why they call libswscale in the beginning, instead of simply using the Y plane. What does this have to do with anything? This sounds like a libswscale or ffmpeg.c problem at best. So what is the API user supposed to do? Special-case by codec? Just what is it? How is this codec-related / when is gray not full-scale (and FFmpeg can know it)? I just want to know how to get non-broken data from lavc? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
wm4 nfxjfg at googlemail.com writes: I thought your question was Do you agree that gray should be full-range? In what context? In all contexts that we can distinguish? Yes, png outputs full range gray, but that doesn't mean other codecs outputting gray do this. Which codec? Note that I am also interested in this, and so far I wasn't able to find an exception except that users have their own requirements that aren't codec-related. Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
wm4 nfxjfg at googlemail.com writes: As said, I had no objections against your patch (on the contrary) but I wonder why you want to set a field that is mostly useful when using libswscale if you don't use libswscale. Uh, what? Do you think libswscale is the only thing that processes video? No, but it seemed to me that this is what your commit message implied. What is your opinion about this? I committed part of the change making gray full range... Whoever wants to use frame-data[0] should use it What do you even mean? I thought your question was Do you agree that gray should be full-range? Some people need the yuv - gray conversion not to change the values, and I always wonder why they call libswscale in the beginning, instead of simply using the Y plane. So what is the API user supposed to do? Special-case by codec? Just what is it? How is this codec-related / when is gray not full-scale (and FFmpeg can know it)? Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
[FFmpeg-devel] [PATCH] pngdec: set correct range
AV_PIX_FMT_GRAY8/16 are considered YUV formats, and the color_range is not set - so the API user will have to assume limitted range. (Unless the API user adds a special-case for the PNG decoder.) Just export the correct range - full range. --- libavcodec/pngdec.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index 1f8a77b..72d75fb 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -633,6 +633,8 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s, return AVERROR_INVALIDDATA; } +avctx-color_range = AVCOL_RANGE_JPEG; + if ((ret = ff_thread_get_buffer(avctx, s-picture, AV_GET_BUFFER_FLAG_REF)) 0) return ret; ff_thread_finish_setup(avctx); -- 2.1.4 ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
wm4 nfxjfg at googlemail.com writes: AV_PIX_FMT_GRAY8/16 are considered YUV formats, and the color_range is not set - so the API user will have to assume limitted range. (Unless the API user adds a special-case for the PNG decoder.) I believe this is slightly misleading: gray8 and gray16 are interpreted as full-range by default since years. This should of course not affect your patch. Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
On Thu, 7 May 2015 22:00:32 + (UTC) Carl Eugen Hoyos ceho...@ag.or.at wrote: wm4 nfxjfg at googlemail.com writes: I believe this is slightly misleading: gray8 and gray16 are interpreted as full-range by default since years. Really? Where? In the software scaler. Doesn't matter much from the API user point of view. Not everyone uses libswscale. There is the (unwritten?) convention that YUV is limited range, and RGB is full range. GRAY is somewhat both, but at least the pixdesc tables do not mark it as RGB. What is your opinion about this? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
On Thu, May 07, 2015 at 11:37:18PM +0200, wm4 wrote: AV_PIX_FMT_GRAY8/16 are considered YUV formats, and the color_range is not set - so the API user will have to assume limitted range. (Unless the API user adds a special-case for the PNG decoder.) Just export the correct range - full range. --- libavcodec/pngdec.c | 2 ++ 1 file changed, 2 insertions(+) applied thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB What does censorship reveal? It reveals fear. -- Julian Assange signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] pngdec: set correct range
wm4 nfxjfg at googlemail.com writes: I believe this is slightly misleading: gray8 and gray16 are interpreted as full-range by default since years. Really? Where? In the software scaler. Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
