avformat/apngenc: use the stream parameters extradata if available

Fixes remuxing apng streams coming from the apng demuxer, which sends extradata
during init.
Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/apngenc.c

@@ -81,6 +81,7 @@ static void apng_write_chunk(AVIOContext *io_context, uint32_t tag,
 static int apng_write_header(AVFormatContext *format_context)
 {
     APNGMuxContext *apng = format_context->priv_data;
+    AVCodecParameters *par = format_context->streams[0]->codecpar;
 
     if (format_context->nb_streams != 1 ||
         format_context->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO ||
@@ -101,6 +102,14 @@ static int apng_write_header(AVFormatContext *format_context)
     avio_wb64(format_context->pb, PNGSIG);
     // Remaining headers are written when they are copied from the encoder
 
+    if (par->extradata_size) {
+        apng->extra_data = av_mallocz(par->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
+        if (!apng->extra_data)
+            return AVERROR(ENOMEM);
+        apng->extra_data_size = par->extradata_size;
+        memcpy(apng->extra_data, par->extradata, par->extradata_size);
+    }
+
     return 0;
 }
 

tests/lavf-regression.sh

@@ -216,9 +216,9 @@ if [ -n "$do_apng" ] ; then
 file=${outfile}lavf.apng
 do_avconv $file $DEC_OPTS -f image2 -vcodec pgmyuv -i $raw_src $ENC_OPTS -t 1 -pix_fmt rgb24
 do_avconv_crc $file $DEC_OPTS -i $target_path/$file -pix_fmt rgb24
-#file_copy=${outfile}lavf.copy.apng
-#do_avconv $file_copy $DEC_OPTS -i $file $ENC_OPTS -c copy
-#do_avconv_crc $file_copy $DEC_OPTS -i $target_path/$file_copy
+file_copy=${outfile}lavf.copy.apng
+do_avconv $file_copy $DEC_OPTS -i $file $ENC_OPTS -c copy
+do_avconv_crc $file_copy $DEC_OPTS -i $target_path/$file_copy
 file=${outfile}lavf.png
 do_avconv $file $DEC_OPTS -f image2 -vcodec pgmyuv -i $raw_src $ENC_OPTS -pix_fmt rgb24 -frames:v 1 -f apng
 do_avconv_crc $file $DEC_OPTS -i $target_path/$file -pix_fmt rgb24

tests/ref/lavf/apng

 a4c46fad7716ad094eb3c78b74ca0244 *./tests/data/lavf/lavf.apng
 6209864 ./tests/data/lavf/lavf.apng
 ./tests/data/lavf/lavf.apng CRC=0x87b3c15f
+a4c46fad7716ad094eb3c78b74ca0244 *./tests/data/lavf/lavf.copy.apng
+6209864 ./tests/data/lavf/lavf.copy.apng
+./tests/data/lavf/lavf.copy.apng CRC=0x87b3c15f
 c5900fdd1b2fc30b985793f5226fd0c4 *./tests/data/lavf/lavf.png
 248854 ./tests/data/lavf/lavf.png
 ./tests/data/lavf/lavf.png CRC=0xd8c7b7a1