From: Kirill Gavrilov <kir...@sview.ru>
Use optional sTER chunk defining side-by-side stereo pair
within "Extensions to the PNG 1.2 Specification", version 1.3.0.
Signed-off-by: Vittorio Giovara <vittorio.giov...@gmail.com>
---
Minor nits, applies to libav, simiplifies reading/setting the mode.
Vittorio
libavcodec/pngdec.c | 18 ++++++++++++++++++
libavcodec/pngenc.c | 22 ++++++++++++++++++++++
2 files changed, 40 insertions(+)
diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 5fa7a2d..b52bf60 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -21,6 +21,8 @@
#include "libavutil/avstring.h"
#include "libavutil/imgutils.h"
+#include "libavutil/stereo3d.h"
+
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
@@ -608,6 +610,22 @@ static int decode_frame(AVCodecContext *avctx,
bytestream2_skip(&s->gb, 4); /* crc */
}
break;
+ case MKTAG('s', 'T', 'E', 'R'): {
+ int mode = bytestream2_get_byte(&s->gb);
+ AVStereo3D *stereo3d = av_stereo3d_create_side_data(p);
+ if (!stereo3d)
+ goto the_end;
+
+ if (mode == 0 || mode == 1) {
+ stereo3d->type = AV_STEREO3D_SIDEBYSIDE;
+ stereo3d->flags = mode ? 0 : AV_STEREO3D_FLAG_INVERT;
+ } else {
+ av_log(avctx, AV_LOG_WARNING,
+ "Unknown value in sTER chunk (%d)\n", mode);
+ }
+ bytestream2_skip(&s->gb, 4); /* crc */
+ break;
+ }
case MKTAG('I', 'E', 'N', 'D'):
if (!(s->state & PNG_ALLIMAGE))
goto fail;
diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 6ab4b7f..96146ac 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -19,6 +19,8 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#include "libavutil/stereo3d.h"
+
#include "avcodec.h"
#include "bytestream.h"
#include "huffyuvencdsp.h"
@@ -233,6 +235,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket
*pkt,
const AVFrame *pict, int *got_packet)
{
PNGEncContext *s = avctx->priv_data;
+ AVFrameSideData *side_data;
const AVFrame *const p = pict;
int bit_depth, color_type, y, len, row_size, ret, is_progressive;
int bits_per_pixel, pass_row_size, enc_row_size, max_packet_size;
@@ -416,6 +419,25 @@ static int encode_frame(AVCodecContext *avctx, AVPacket
*pkt,
top = ptr;
}
}
+
+ /* write stereoscopic information */
+ side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_STEREO3D);
+ if (side_data) {
+ AVStereo3D *stereo3d = (AVStereo3D *)side_data->data;
+ switch (stereo3d->type) {
+ case AV_STEREO3D_SIDEBYSIDE:
+ s->buf[0] = !(stereo3d->flags & AV_STEREO3D_FLAG_INVERT);
+ png_write_chunk(&s->bytestream, MKTAG('s', 'T', 'E', 'R'), s->buf,
1);
+ break;
+ case AV_STEREO3D_2D:
+ break;
+ default:
+ av_log(avctx, AV_LOG_WARNING,
+ "Only side-by-side stereo3d flag can be defined within sTER
chunk\n");
+ break;
+ }
+ }
+
/* compress last bytes */
for (;;) {
ret = deflate(&s->zstream, Z_FINISH);
--
1.9.5 (Apple Git-50.3)
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