avformat/apngenc: Check fcTL size

The remaining code relies on it having the value it should have.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2022-07-04 15:35:04 +02:00
parent 3204572a1a
commit f89446eaff

View File

@ -27,6 +27,7 @@
#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavcodec/apng.h"
#include "libavcodec/png.h"
typedef struct APNGMuxContext {
@ -181,6 +182,9 @@ static int flush_packet(AVFormatContext *format_context, AVPacket *packet)
if (existing_fcTL_chunk) {
AVRational delay;
if (AV_RB32(existing_fcTL_chunk) != APNG_FCTL_CHUNK_SIZE)
return AVERROR_INVALIDDATA;
existing_fcTL_chunk += 8;
delay.num = AV_RB16(existing_fcTL_chunk + 20);
delay.den = AV_RB16(existing_fcTL_chunk + 22);