Jan Ekström (12020-09-16):
> This value - while it looks like the actual range of the content -
> is nothing but the internal value of swscale.
>
> Thus, if we have RGB content, force the value to 1. Swscale will
> ignore it, but at least the value of the output AVFrame will now
> properly be "full range" instead of "limited range", as it is right
> now.
> ---
> libavfilter/vf_scale.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
> index 58eee96744..12df27edf4 100644
> --- a/libavfilter/vf_scale.c
> +++ b/libavfilter/vf_scale.c
> @@ -751,6 +751,15 @@ scale:
> || scale->out_range != AVCOL_RANGE_UNSPECIFIED) {
> int in_full, out_full, brightness, contrast, saturation;
> const int *inv_table, *table;
> + const AVPixFmtDescriptor *out_desc =
> av_pix_fmt_desc_get(out->format);
> + if (!out_desc) {
> + av_log(ctx, AV_LOG_ERROR,
> + "Failed to get the pixel format descriptor for format
> %d!\n",
> + out->format);
> + av_frame_free(&in);
> + av_frame_free(frame_out);
> + return AVERROR_INVALIDDATA;
> + }
Since the format is negotiated, I think it can be considered a severe
internal bug that out_desc is not found, i.e. checked by an assert.
>
> sws_getColorspaceDetails(scale->sws, (int **)&inv_table, &in_full,
> (int **)&table, &out_full,
> @@ -768,7 +777,15 @@ scale:
> else if (in_range != AVCOL_RANGE_UNSPECIFIED)
> in_full = (in_range == AVCOL_RANGE_JPEG);
> if (scale->out_range != AVCOL_RANGE_UNSPECIFIED)
> + // note: this can be silently overridden by
> + // sws_setColorspaceDetails for non-YCbCr formats
> out_full = (scale->out_range == AVCOL_RANGE_JPEG);
> + else if (out_desc->flags & AV_PIX_FMT_FLAG_RGB)
> + // the range values received from swscale are its internal
> + // identifiers, and will not be nonzero for any sort of RGB.
> + // thus, if we do not set it to nonzero ourselves, this will
> + // be incorrect.
> + out_full = 1;
>
> sws_setColorspaceDetails(scale->sws, inv_table, in_full,
> table, out_full,
With you explanation, I think it is ok, but I do not know the topic
enough to be sure.
Regards,
--
Nicolas George
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