On Fri, Feb 3, 2017 at 2:10 PM, Kieran O Leary <kieran.o.le...@gmail.com> wrote: > Hi Vittorio! > > thanks for getting back to me. > > On Fri, Feb 3, 2017 at 12:57 PM, Vittorio Giovara > <vittorio.giov...@gmail.com> wrote: >> >> >> >> Hey Kieran, >> I think the code looks fine. I am just wondering if we should also >> offer the possibility to set these flags from the standard context >> options (-color_trc and others). I'm aware that not all values match >> or are valid but maybe a small conversion table or extending the main >> table could be a viable approach. Similarly this could be done for the >> decoder so that color properties are not lost during a dpx->dpx >> conversion maybe. > > > That seems to be the general consensus from the replies from James Almer and > Carl Eugen and it's what i should push towards. > I added the new values locally to pixfmt.h. I'm thinking that these could be > called in a similar way to the EXR decoder? > https://github.com/FFmpeg/FFmpeg/blob/8a1759ad46f05375c957f33049b4592befbcb224/libavcodec/exr.c#L1840
Not sure to which changes you mean, all the values listed by that commit are already supported by the current AVColorTransferCharacteristic implementation. Incidentally, I believe that the codec you point to is a perfect examples of something libavcodec should not do, color conversion in a decoder: in my opinion this a task that should be reserved for something external such as lavfi or ideally lsws. > In terms of translation tables, could you point me to some simlar code that > could serve as a starting point for me? The nearest that made sense to me > seems to be these values in vf_colorpsace.c > https://github.com/FFmpeg/FFmpeg/blob/master/libavfilter/vf_colorspace.c#L97 > ? I didn't explain myself well enough, I was mainly suggesting that rather than having a private option used to tag the final output, you could *also* read the standard command line option in avctx->color_trc and use it to tag the output. Since you can't reuse the value because dpx seem to use a different table, you should translate the value from AVColorTransferCharacteristic to whatever dpx accepts. In pseudocode if (priv_trc_opt = "") { if (avctx->color_trc == AVCOL_BT709) buf[801] = DPX_BT709 else if (avctx->color_trc == AVCOL_BT601) buf[801] = DPX_BT601 ... } else buf[801] = priv_trc_opt -- Vittorio _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
