Add support for properly handling PC/TV ranges and Rec601/Rec709 color spaces.
Example for PC range YUV, compare to ImageMagick decoding:
https://samples.ffmpeg.org/image-samples/dscf0013.tif
From 5e24edbf73f3a897fd203e36963e9cf5db5e688d Mon Sep 17 00:00:00 2001
From: Pavel Skakov <pave...@gmail.com>
Date: Thu, 3 Oct 2019 21:28:10 +0300
Subject: [PATCH] avcodec/tiff: add limited support for ReferenceBlackWhite and
YCbCrCoefficients tags
Signed-off-by: Pavel Skakov <pave...@gmail.com>
---
libavcodec/tiff.c | 74 ++++++++++++++++++++++++++++++++++++++++--
tests/ref/fate/exif-image-tiff | 2 +-
2 files changed, 73 insertions(+), 3 deletions(-)
diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 8b39ca1ebc..90215fce09 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -1441,12 +1441,16 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
break;
case TIFF_PHOTOMETRIC:
switch (value) {
+ case TIFF_PHOTOMETRIC_YCBCR:
+ s->avctx->colorspace = AVCOL_SPC_BT470BG;
+ // fallthrough
+ case TIFF_PHOTOMETRIC_RGB:
+ s->avctx->color_range = AVCOL_RANGE_JPEG;
+ // fallthrough
case TIFF_PHOTOMETRIC_WHITE_IS_ZERO:
case TIFF_PHOTOMETRIC_BLACK_IS_ZERO:
- case TIFF_PHOTOMETRIC_RGB:
case TIFF_PHOTOMETRIC_PALETTE:
case TIFF_PHOTOMETRIC_SEPARATED:
- case TIFF_PHOTOMETRIC_YCBCR:
case TIFF_PHOTOMETRIC_CFA:
case TIFF_PHOTOMETRIC_LINEAR_RAW: // Used by DNG images
s->photometric = value;
@@ -1519,6 +1523,72 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
}
}
break;
+ case TIFF_YCBCR_COEFFICIENTS:
+ if (s->photometric == TIFF_PHOTOMETRIC_YCBCR)
+ if (count != 3 || type != TIFF_RATIONAL) {
+ av_log(s->avctx, AV_LOG_ERROR, "YCbCrCoefficients are invalid\n");
+ return AVERROR_INVALIDDATA;
+ } else {
+ // LibTIFF handles rational values by converting them to/from floats, so we do the same in tests for equality
+ float coef[3];
+ for (i = 0; i < 3; i++) {
+ unsigned num = ff_tget(&s->gb, TIFF_LONG, s->le);
+ unsigned den = ff_tget(&s->gb, TIFF_LONG, s->le);
+ if (!den) {
+ av_log(s->avctx, AV_LOG_ERROR, "YCbCrCoefficients divisor is zero\n");
+ return AVERROR_INVALIDDATA;
+ }
+ coef[i] = (float)num/den;
+ }
+ if (coef[0] == 0.2125f && coef[1] == 0.7154f && coef[2] == 0.0721f)
+ s->avctx->colorspace = AVCOL_SPC_BT709;
+ else if (coef[0] != 0.299f || coef[1] != 0.587f || coef[2] != 0.114f) {
+ av_log(s->avctx, AV_LOG_WARNING, "Unrecognized YCbCrCoefficients values: %.4f %.4f %.4f\n", coef[0], coef[1], coef[2]);
+ s->avctx->colorspace = AVCOL_SPC_UNSPECIFIED;
+ }
+ }
+ break;
+ case TIFF_REFERENCE_BW:
+ if (s->photometric == TIFF_PHOTOMETRIC_YCBCR || s->photometric == TIFF_PHOTOMETRIC_RGB)
+ if (count != 6 || type != TIFF_RATIONAL) {
+ av_log(s->avctx, AV_LOG_ERROR, "ReferenceBlackWhite is invalid\n");
+ return AVERROR_INVALIDDATA;
+ } else {
+ unsigned bpp = s->bpp/s->bppcount;
+ unsigned mul = 1 << (bpp - 8);
+ float max_val = (1 << bpp) - 1;
+ float coef[6];
+ for (i = 0; i < 6; i++) {
+ unsigned num = ff_tget(&s->gb, TIFF_LONG, s->le);
+ unsigned den = ff_tget(&s->gb, TIFF_LONG, s->le);
+ if (!den) {
+ av_log(s->avctx, AV_LOG_ERROR, "ReferenceBlackWhite divisor is zero\n");
+ return AVERROR_INVALIDDATA;
+ }
+ coef[i] = (float)num/den;
+ }
+ if (s->photometric == TIFF_PHOTOMETRIC_YCBCR) {
+ if (!coef[0] && coef[1] == max_val && coef[2] == (max_val + 1)/2 && coef[3] == max_val && coef[4] == coef[2] && coef[5] == coef[3])
+ s->avctx->color_range = AVCOL_RANGE_JPEG;
+ // NOTE: TIFF 6.0 specification has an example where it mistakenly shows TV range coef[0] as 15
+ else if (coef[0] == 16*mul && coef[1] == 235*mul && coef[2] == 128*mul && coef[3] == 240*mul && coef[4] == coef[2] && coef[5] == coef[3])
+ s->avctx->color_range = AVCOL_RANGE_MPEG;
+ else {
+ av_log(s->avctx, AV_LOG_WARNING, "Unrecognized ReferenceBlackWhite values: [%g;%g] [%g;%g] [%g;%g]\n", coef[0], coef[1], coef[2], coef[3], coef[4], coef[5]);
+ s->avctx->color_range = AVCOL_RANGE_UNSPECIFIED;
+ }
+ } else {
+ if (!coef[0] && coef[1] == max_val && !coef[2] && coef[3] == max_val && !coef[4] && coef[5] == max_val)
+ s->avctx->color_range = AVCOL_RANGE_JPEG;
+ else if (coef[0] == 16*mul && coef[1] == 235*mul && coef[2] == coef[0] && coef[3] == coef[1] && coef[2] == coef[0] && coef[3] == coef[1])
+ s->avctx->color_range = AVCOL_RANGE_MPEG;
+ else {
+ av_log(s->avctx, AV_LOG_WARNING, "Unrecognized ReferenceBlackWhite values: [%g;%g] [%g;%g] [%g;%g]\n", coef[0], coef[1], coef[2], coef[3], coef[4], coef[5]);
+ s->avctx->color_range = AVCOL_RANGE_UNSPECIFIED;
+ }
+ }
+ }
+ break;
case TIFF_T4OPTIONS:
if (s->compr == TIFF_G3)
s->fax_opts = value;
diff --git a/tests/ref/fate/exif-image-tiff b/tests/ref/fate/exif-image-tiff
index 51580601e1..ebf2f38d6e 100644
--- a/tests/ref/fate/exif-image-tiff
+++ b/tests/ref/fate/exif-image-tiff
@@ -22,7 +22,7 @@ display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
-color_range=unknown
+color_range=pc
color_space=unknown
color_primaries=unknown
color_transfer=unknown
--
2.13.2.windows.1
_______________________________________________
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".
