[FFmpeg-cvslog] avformat/apngenc: Don't modify input packet
Andreas Rheinhardt
git at videolan.org
Sat Jul 9 20:46:01 EEST 2022
ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Mon Jul 4 17:04:15 2022 +0200| [05e96e69334529198acea0a64718202119cd314b] | committer: Andreas Rheinhardt
avformat/apngenc: Don't modify input packet
It might not be writable at this point.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=05e96e69334529198acea0a64718202119cd314b
---
libavformat/apngenc.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/libavformat/apngenc.c b/libavformat/apngenc.c
index 1c039685f2..c219b80161 100644
--- a/libavformat/apngenc.c
+++ b/libavformat/apngenc.c
@@ -159,6 +159,7 @@ static int flush_packet(AVFormatContext *format_context, AVPacket *packet)
avio_write(io_context, apng->prev_packet->data, apng->prev_packet->size);
}
} else {
+ const uint8_t *data, *data_end;
uint8_t *existing_fcTL_chunk;
if (apng->frame_number == 0) {
@@ -178,6 +179,8 @@ static int flush_packet(AVFormatContext *format_context, AVPacket *packet)
}
}
+ data = apng->prev_packet->data;
+ data_end = data + apng->prev_packet->size;
existing_fcTL_chunk = apng_find_chunk(MKBETAG('f', 'c', 'T', 'L'), apng->prev_packet->data, apng->prev_packet->size);
if (existing_fcTL_chunk) {
AVRational delay;
@@ -190,6 +193,8 @@ static int flush_packet(AVFormatContext *format_context, AVPacket *packet)
delay.den = AV_RB16(existing_fcTL_chunk + 22);
if (delay.num == 0 && delay.den == 0) {
+ uint8_t new_fcTL_chunk[APNG_FCTL_CHUNK_SIZE];
+
if (packet) {
int64_t delay_num_raw = (packet->dts - apng->prev_packet->dts) * codec_stream->time_base.num;
int64_t delay_den_raw = codec_stream->time_base.den;
@@ -205,16 +210,20 @@ static int flush_packet(AVFormatContext *format_context, AVPacket *packet)
delay = apng->prev_delay;
}
+ avio_write(io_context, data, (existing_fcTL_chunk - 8) - data);
+ data = existing_fcTL_chunk + APNG_FCTL_CHUNK_SIZE + 4 /* CRC-32 */;
// Update frame control header with new delay
- AV_WB16(existing_fcTL_chunk + 20, delay.num);
- AV_WB16(existing_fcTL_chunk + 22, delay.den);
- AV_WB32(existing_fcTL_chunk + 26, ~av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), ~0U, existing_fcTL_chunk - 4, 26 + 4));
+ memcpy(new_fcTL_chunk, existing_fcTL_chunk, sizeof(new_fcTL_chunk));
+ AV_WB16(new_fcTL_chunk + 20, delay.num);
+ AV_WB16(new_fcTL_chunk + 22, delay.den);
+ apng_write_chunk(io_context, MKBETAG('f', 'c', 'T', 'L'),
+ new_fcTL_chunk, sizeof(new_fcTL_chunk));
}
apng->prev_delay = delay;
}
// Write frame data
- avio_write(io_context, apng->prev_packet->data, apng->prev_packet->size);
+ avio_write(io_context, data, data_end - data);
}
++apng->frame_number;
More information about the ffmpeg-cvslog
mailing list