It looks like the handling of "video" range (16-235) sources (when
creating "full" range (0-255) outputs) has been broken for some considerable
time. Full range outputs are used for both preview and DCP creation.
We assumed that after we called sws_setColorspaceDetails FFmpeg would take
care of the conversion from video to full, but its source suggests that
it refuses to convert to full-range RGB (only full-range YUV or
greyscale). Previously there was a seemingly correct comment (that
FFmpeg would do nothing if source _or_ destination were RGB) but the
check on when to use video_range_to_full_range() was only activated
for RGB sources, not (also) RGB outputs.
It's hard to believe that this has been around unnoticed for so long.
https://dcpomatic.com/forum/viewtopic.php?t=1928&start=10 has a
discussion which pointed out the problem.
1 -> destination range JPEG (i.e. "full", 0-255)
But remember: sws_setColorspaceDetails ignores these
1 -> destination range JPEG (i.e. "full", 0-255)
But remember: sws_setColorspaceDetails ignores these
- parameters unless the both source and destination images
+ parameters unless both source and destination images
are isYUV or isGray. (If either is not, it uses video range).
*/
sws_setColorspaceDetails (
are isYUV or isGray. (If either is not, it uses video range).
*/
sws_setColorspaceDetails (
if (
video_range == VideoRange::VIDEO &&
out_video_range == VideoRange::FULL &&
if (
video_range == VideoRange::VIDEO &&
out_video_range == VideoRange::FULL &&
- av_pix_fmt_desc_get(_pixel_format)->flags & AV_PIX_FMT_FLAG_RGB
+ ((av_pix_fmt_desc_get(_pixel_format)->flags & AV_PIX_FMT_FLAG_RGB) ||
+ (av_pix_fmt_desc_get(out_format)->flags & AV_PIX_FMT_FLAG_RGB))
- /* libswscale will not convert video range for RGB sources, so we have to do it ourselves */
+ /* libswscale will not convert video range if input or output is RGB, as far as I can see,
+ * so we have to do it ourselves.
+ */
out->video_range_to_full_range ();
}
out->video_range_to_full_range ();
}