[FFmpeg-devel] [PATCH 1/4] avformat/demux: don't propagate unsupported skip samples packet side data values

[FFmpeg-devel] [PATCH 1/4] avformat/demux: don't propagate unsupported skip samples packet side data values

[James Almer]

Should fix ticket #9622

Signed-off-by: James Almer <jamrial@gmail.com>
---
I'm not sure if this is ok or not. The AV_PKT_DATA_SKIP_SAMPLES doxy states
the skip samples value is a little endian uint32 value, so even if the mov
demuxer wrote a truncated int64_t value in sti->skip_samples (which, being an
int, can be negative), it would still be "valid" when written into the packet
as side data.

Chromium's fix is https://chromium-review.googlesource.com/c/chromium/src/+/3424556
where you can see they have been reading the skip samples value from
AV_PKT_DATA_SKIP_SAMPLES as an int.

 libavformat/demux.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavformat/demux.c b/libavformat/demux.c
index f895f0ba85..09d539af68 100644
--- a/libavformat/demux.c
+++ b/libavformat/demux.c
@@ -1354,6 +1354,7 @@ static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
         }
         if (sti->start_skip_samples && (pkt->pts == 0 || pkt->pts == RELATIVE_TS_BASE))
             sti->skip_samples = sti->start_skip_samples;
+        sti->skip_samples = FFMAX(0, sti->skip_samples);
         if (sti->skip_samples || discard_padding) {
             uint8_t *p = av_packet_new_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES, 10);
             if (p) {
-- 
2.34.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH 2/4] avcodec/decode: ignore unsupported skip samples packet side data values

[James Almer]

Same as in the AV_FRAME_FLAG_DISCARD codepath, ensure avci->skip_samples is not
negative.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/decode.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 0912f86a14..4f9b949926 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -366,6 +366,7 @@ static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame,
         side= av_packet_get_side_data(avci->last_pkt_props, AV_PKT_DATA_SKIP_SAMPLES, &side_size);
         if(side && side_size>=10) {
             avci->skip_samples = AV_RL32(side) * avci->skip_samples_multiplier;
+            avci->skip_samples = FFMAX(0, avci->skip_samples);
             discard_padding = AV_RL32(side + 4);
             av_log(avctx, AV_LOG_DEBUG, "skip %d / discard %d samples due to side data\n",
                    avci->skip_samples, (int)discard_padding);
-- 
2.34.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH 3/4] avformat/demux: print skip_samples and discard_padding as unsigned values in debug log

[James Almer]

It's the type they should be interpreted as in the AV_PKT_DATA_SKIP_SAMPLES side
data.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavformat/demux.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/demux.c b/libavformat/demux.c
index 09d539af68..4509015847 100644
--- a/libavformat/demux.c
+++ b/libavformat/demux.c
@@ -1360,7 +1360,8 @@ static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
             if (p) {
                 AV_WL32(p, sti->skip_samples);
                 AV_WL32(p + 4, discard_padding);
-                av_log(s, AV_LOG_DEBUG, "demuxer injecting skip %d / discard %d\n", sti->skip_samples, discard_padding);
+                av_log(s, AV_LOG_DEBUG, "demuxer injecting skip %u / discard %u\n",
+                       (unsigned)sti->skip_samples, (unsigned)discard_padding);
             }
             sti->skip_samples = 0;
         }
-- 
2.34.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH 4/4] avformat/demux: don't truncate the return value of ts_to_samples()

[James Almer]

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavformat/demux.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/demux.c b/libavformat/demux.c
index 4509015847..ec34b65288 100644
--- a/libavformat/demux.c
+++ b/libavformat/demux.c
@@ -1346,7 +1346,7 @@ static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
         if (sti->first_discard_sample && pkt->pts != AV_NOPTS_VALUE) {
             int64_t pts = pkt->pts - (is_relative(pkt->pts) ? RELATIVE_TS_BASE : 0);
             int64_t sample = ts_to_samples(st, pts);
-            int duration = ts_to_samples(st, pkt->duration);
+            int64_t duration = ts_to_samples(st, pkt->duration);
             int64_t end_sample = sample + duration;
             if (duration > 0 && end_sample >= sti->first_discard_sample &&
                 sample < sti->last_discard_sample)
-- 
2.34.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH 1/4] avformat/demux: don't propagate unsupported skip samples packet side data values

[James Almer]

On 1/31/2022 10:56 PM, James Almer wrote:
> Should fix ticket #9622
> 
> Signed-off-by: James Almer <jamrial@gmail.com>
> ---
> I'm not sure if this is ok or not. The AV_PKT_DATA_SKIP_SAMPLES doxy states
> the skip samples value is a little endian uint32 value, so even if the mov
> demuxer wrote a truncated int64_t value in sti->skip_samples (which, being an
> int, can be negative), it would still be "valid" when written into the packet
> as side data.
> 
> Chromium's fix is https://chromium-review.googlesource.com/c/chromium/src/+/3424556
> where you can see they have been reading the skip samples value from
> AV_PKT_DATA_SKIP_SAMPLES as an int.
> 
>   libavformat/demux.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/libavformat/demux.c b/libavformat/demux.c
> index f895f0ba85..09d539af68 100644
> --- a/libavformat/demux.c
> +++ b/libavformat/demux.c
> @@ -1354,6 +1354,7 @@ static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
>           }
>           if (sti->start_skip_samples && (pkt->pts == 0 || pkt->pts == RELATIVE_TS_BASE))
>               sti->skip_samples = sti->start_skip_samples;
> +        sti->skip_samples = FFMAX(0, sti->skip_samples);
>           if (sti->skip_samples || discard_padding) {
>               uint8_t *p = av_packet_new_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES, 10);
>               if (p) {

Will apply patchset.
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".