From: Niklas Haas <g...@haasn.dev>
encode_zbuf is mostly a mirror image of decode_zbuf. Other than that,
the code is pretty straightforward. Special care needs to be taken to
avoid writing more than 79 characters of the profile description (the
maximum supported).
Also add a FATE transcode test to ensure that the ICC profile gets
encoded correctly.
---
Oops. `-c copy` doesn't actually test the PNG writing code. Need to use
`-c png` instead. Fixed in v2.
---
libavcodec/pngenc.c | 77 +++++++++++++++++++++++++++++++++++++++++-
tests/fate/image.mak | 3 ++
tests/ref/fate/png-icc | 8 +++++
3 files changed, 87 insertions(+), 1 deletion(-)
create mode 100644 tests/ref/fate/png-icc
diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 3ebcc1e571..24530bb62f 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -28,6 +28,7 @@
#include "apng.h"
#include "libavutil/avassert.h"
+#include "libavutil/bprint.h"
#include "libavutil/crc.h"
#include "libavutil/libm.h"
#include "libavutil/opt.h"
@@ -343,6 +344,65 @@ static int png_get_gama(enum AVColorTransferCharacteristic
trc, uint8_t *buf)
return 1;
}
+static int encode_zbuf(AVBPrint *bp, const uint8_t *data, size_t size)
+{
+ z_stream zstream;
+ unsigned char *buf;
+ unsigned buf_size;
+ int ret;
+
+ zstream.zalloc = ff_png_zalloc,
+ zstream.zfree = ff_png_zfree,
+ zstream.opaque = NULL;
+ if (deflateInit(&zstream, Z_DEFAULT_COMPRESSION) != Z_OK)
+ return AVERROR_EXTERNAL;
+ zstream.next_in = data;
+ zstream.avail_in = size;
+
+ for (;;) {
+ av_bprint_get_buffer(bp, 2, &buf, &buf_size);
+ if (buf_size < 2) {
+ deflateEnd(&zstream);
+ return AVERROR(ENOMEM);
+ }
+
+ zstream.next_out = buf;
+ zstream.avail_out = buf_size - 1;
+ ret = deflate(&zstream, Z_FINISH);
+ if (ret != Z_OK && ret != Z_STREAM_END) {
+ deflateEnd(&zstream);
+ return AVERROR_EXTERNAL;
+ }
+
+ bp->len += zstream.next_out - buf;
+ if (ret == Z_STREAM_END) {
+ deflateEnd(&zstream);
+ return 0;
+ }
+ }
+}
+
+static int png_get_iccp(AVBPrint *bp, const AVFrameSideData *sd, char
**buf_out)
+{
+ const AVDictionaryEntry *name;
+ int ret;
+
+ av_bprint_init(bp, 0, AV_BPRINT_SIZE_UNLIMITED);
+
+ /* profile header */
+ name = av_dict_get(sd->metadata, "name", NULL, 0);
+ av_bprintf(bp, "%.79s", (name && name->value[0]) ? name->value : "icc");
+ av_bprint_chars(bp, 0, 2); /* terminating \0 and compression method */
+
+ /* profile data */
+ if ((ret = encode_zbuf(bp, sd->data, sd->size))) {
+ av_bprint_finalize(bp, NULL);
+ return ret;
+ }
+
+ return av_bprint_finalize(bp, buf_out);
+}
+
static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
{
AVFrameSideData *side_data;
@@ -399,7 +459,22 @@ static int encode_headers(AVCodecContext *avctx, const
AVFrame *pict)
if (png_get_gama(pict->color_trc, s->buf))
png_write_chunk(&s->bytestream, MKTAG('g', 'A', 'M', 'A'), s->buf, 4);
- /* put the palette if needed */
+ side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
+ if (side_data && side_data->size) {
+ AVBPrint bp;
+ char *buf;
+ int ret;
+
+ if ((ret = png_get_iccp(&bp, side_data, &buf))) {
+ av_log(avctx, AV_LOG_WARNING, "Failed writing iCCP chunk: %s\n",
+ av_err2str(ret));
+ } else {
+ png_write_chunk(&s->bytestream, MKTAG('i', 'C', 'C', 'P'), buf,
bp.size);
+ av_free(buf);
+ }
+ }
+
+ /* put the palette if needed, must be after colorspace information */
if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
int has_alpha, alpha, i;
unsigned int v;
diff --git a/tests/fate/image.mak b/tests/fate/image.mak
index 573d398915..da4f3709e9 100644
--- a/tests/fate/image.mak
+++ b/tests/fate/image.mak
@@ -385,6 +385,9 @@ FATE_PNG_PROBE += fate-png-side-data
fate-png-side-data: CMD = run ffprobe$(PROGSSUF)$(EXESUF) -show_frames \
-i $(TARGET_SAMPLES)/png1/lena-int_rgb24.png
+FATE_PNG_PROBE += fate-png-icc
+fate-png-icc: CMD = transcode png_pipe
$(TARGET_SAMPLES)/png1/lena-int_rgb24.png image2 "-c png"
+
FATE_PNG-$(call DEMDEC, IMAGE2, PNG) += $(FATE_PNG)
FATE_PNG_PROBE-$(call DEMDEC, IMAGE2, PNG) += $(FATE_PNG_PROBE)
FATE_IMAGE += $(FATE_PNG-yes)
diff --git a/tests/ref/fate/png-icc b/tests/ref/fate/png-icc
new file mode 100644
index 0000000000..d3cf55263e
--- /dev/null
+++ b/tests/ref/fate/png-icc
@@ -0,0 +1,8 @@
+7e412f6a9e2c7fcb674336e5c104518d *tests/data/fate/png-icc.image2
+49398 tests/data/fate/png-icc.image2
+#tb 0: 1/25
+#media_type 0: video
+#codec_id 0: rawvideo
+#dimensions 0: 128x128
+#sar 0: 2835/2835
+0, 0, 0, 1, 49152, 0xe0013dee
--
2.35.1
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