avcodec/pngenc: support writing EXIF profiles

Add support to write EXIF profiles using the new EXIF framework, namely
ff_exif_get_buffer, and writing them into eXIf chunks.

Signed-off-by: Leo Izen <[email protected]>

4 files changed, 29 insertions, 6 deletions

diff --git a/libavcodec/exif.c b/libavcodec/exif.c
index c48eb5daa6..fa46202874 100644
--- a/libavcodec/exif.c
+++ b/libavcodec/exif.c
@@ -1350,6 +1350,13 @@ int ff_exif_get_buffer(void *logctx, const AVFrame *frame, AVBufferRef **buffer_
     }
     if (!pw && w && w < 0xFFFFu || !ph && h && h < 0xFFFFu) {
         rewrite = 1;
+        exif = NULL;
+        for (size_t i = 0; i < ifd.count; i++) {
+            if (ifd.entries[i].id == EXIFIFD_TAG && ifd.entries[i].type == AV_TIFF_IFD) {
+                exif = &ifd.entries[i].value.ifd;
+                break;
+            }
+        }
         if (!exif) {
             AVExifMetadata exif_new = { 0 };
             ret = av_exif_set_entry(logctx, &ifd, EXIFIFD_TAG, AV_TIFF_IFD, 1, NULL, 0, &exif_new);
diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 9bbb8267cf..635c89e87e 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -22,6 +22,7 @@
 #include "avcodec.h"
 #include "codec_internal.h"
 #include "encode.h"
+#include "exif_internal.h"
 #include "bytestream.h"
 #include "lossless_videoencdsp.h"
 #include "png.h"
@@ -29,6 +30,7 @@
 #include "zlib_wrapper.h"
 
 #include "libavutil/avassert.h"
+#include "libavutil/buffer.h"
 #include "libavutil/crc.h"
 #include "libavutil/csp.h"
 #include "libavutil/libm.h"
@@ -373,6 +375,7 @@ static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
 {
     AVFrameSideData *side_data;
     PNGEncContext *s = avctx->priv_data;
+    AVBufferRef *exif_data = NULL;
     int ret;
 
     /* write png header */
@@ -414,6 +417,19 @@ static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
         }
     }
 
+    ret = ff_exif_get_buffer(avctx, pict, &exif_data, AV_EXIF_TIFF_HEADER);
+    if (exif_data) {
+        // png_write_chunk accepts an int, not a size_t, so we have to check overflow
+        if (exif_data->size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
+            // that's a very big exif chunk, probably a bug
+            av_log(avctx, AV_LOG_ERROR, "extremely large EXIF buffer detected, not writing\n");
+        else
+            png_write_chunk(&s->bytestream, MKTAG('e','X','I','f'), exif_data->data, exif_data->size);
+        av_buffer_unref(&exif_data);
+    } else if (ret < 0) {
+        av_log(avctx, AV_LOG_WARNING, "unable to attach EXIF metadata: %s\n", av_err2str(ret));
+    }
+
     side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
     if ((ret = png_write_iccp(s, side_data)))
         return ret;
diff --git a/tests/ref/fate/cover-art-mp3-id3v2-remux b/tests/ref/fate/cover-art-mp3-id3v2-remux
index 011c123a70..42fe704470 100644
--- a/tests/ref/fate/cover-art-mp3-id3v2-remux
+++ b/tests/ref/fate/cover-art-mp3-id3v2-remux
@@ -1,5 +1,5 @@
-a8dc078d174d5c4ae9769090b8404bae *tests/data/fate/cover-art-mp3-id3v2-remux.mp3
-346394 tests/data/fate/cover-art-mp3-id3v2-remux.mp3
+070ed1d95dc1bd365d68ae795966589f *tests/data/fate/cover-art-mp3-id3v2-remux.mp3
+346509 tests/data/fate/cover-art-mp3-id3v2-remux.mp3
 #tb 0: 1/14112000
 #media_type 0: audio
 #codec_id 0: mp3
@@ -23,7 +23,7 @@ a8dc078d174d5c4ae9769090b8404bae *tests/data/fate/cover-art-mp3-id3v2-remux.mp3
 0,    -353590,    -353590,   368640,      417, 0x15848290, S=1, Skip Samples,       10, 0x034e0055
 1,          0,          0,        0,   208350, 0x291b44d1
 2,          0,          0,        0,    15760, 0x71d5c418
-3,          0,          0,        0,   112719, 0x117b6853
+3,          0,          0,        0,   112834, 0x7da17554
 0,      15050,      15050,   368640,      418, 0x46f684a4
 0,     383690,     383690,   368640,      418, 0x46f684a4
 0,     752330,     752330,   368640,      418, 0x46f684a4
diff --git a/tests/ref/fate/mov-cover-image b/tests/ref/fate/mov-cover-image
index 0607d56a0c..305a851d98 100644
--- a/tests/ref/fate/mov-cover-image
+++ b/tests/ref/fate/mov-cover-image
@@ -1,5 +1,5 @@
-9a5143f063aedb39fb1f080444cc19a0 *tests/data/fate/mov-cover-image.mp4
-1023905 tests/data/fate/mov-cover-image.mp4
+ea8251f5922d663b174855af325d689f *tests/data/fate/mov-cover-image.mp4
+1024065 tests/data/fate/mov-cover-image.mp4
 #extradata 0:        2, 0x00340022
 #tb 0: 1/44100
 #media_type 0: audio
@@ -20,7 +20,7 @@
 0,      -1088,      -1088,     1024,        6, 0x027e00e8, F=0x5
 0,        -64,        -64,     1024,        6, 0x027e00e8
 1,          0,          0,        0,    25441, 0xe82503b0
-2,          0,          0,        0,    44643, 0xdb75ffb5
+2,          0,          0,        0,    44803, 0x1e4a0e8f
 0,        960,        960,     1024,        6, 0x027e00e8
 0,       1984,       1984,     1024,        6, 0x027e00e8
 0,       3008,       3008,     1024,        6, 0x027e00e8