diff mbox series

[FFmpeg-devel,01/10] avformat/mux: Only prepare input packet if there is a packet

Message ID 20200331123745.6461-2-andreas.rheinhardt@gmail.com
State Accepted
Headers show
Series libavformat/mux patches
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Commit Message

Andreas Rheinhardt March 31, 2020, 12:37 p.m. UTC
It is unnecessary to call prepare_input_packet if there is no packet as
it doesn't do anything, except when the currently inactive code guarded
by !FF_API_COMPUTE_PKT_FIELDS2 || !FF_API_LAVF_AVCTX becomes active:
Then attempting to access pkt->stream_index will crash.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
---
This works very well together with Marton's patch #4 [1]:
write_packets_common(): The prepare_input_packet() call can be moved
into write_packets_common(). Unfortunately, it's not compatible with #5
[2] as-is, but I think I have a solution for this.

[1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259203.html
[2]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259204.html

 libavformat/mux.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

Comments

Marton Balint March 31, 2020, 7:33 p.m. UTC | #1
On Tue, 31 Mar 2020, Andreas Rheinhardt wrote:

> It is unnecessary to call prepare_input_packet if there is no packet as
> it doesn't do anything, except when the currently inactive code guarded
> by !FF_API_COMPUTE_PKT_FIELDS2 || !FF_API_LAVF_AVCTX becomes active:
> Then attempting to access pkt->stream_index will crash.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
> ---
> This works very well together with Marton's patch #4 [1]:
> write_packets_common(): The prepare_input_packet() call can be moved
> into write_packets_common(). Unfortunately, it's not compatible with #5
> [2] as-is, but I think I have a solution for this.
>
> [1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259203.html
> [2]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259204.html
>
> libavformat/mux.c | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/libavformat/mux.c b/libavformat/mux.c
> index bfd1bf491b..814d773b9d 100644
> --- a/libavformat/mux.c
> +++ b/libavformat/mux.c
> @@ -771,9 +771,6 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
> 
> static int check_packet(AVFormatContext *s, AVPacket *pkt)
> {
> -    if (!pkt)
> -        return 0;
> -
>     if (pkt->stream_index < 0 || pkt->stream_index >= s->nb_streams) {
>         av_log(s, AV_LOG_ERROR, "Invalid packet stream index: %d\n",
>                pkt->stream_index);
> @@ -887,10 +884,6 @@ int av_write_frame(AVFormatContext *s, AVPacket *pkt)
> {
>     int ret;
> 
> -    ret = prepare_input_packet(s, pkt);
> -    if (ret < 0)
> -        return ret;
> -
>     if (!pkt) {
>         if (s->oformat->flags & AVFMT_ALLOW_FLUSH) {
>             ret = s->oformat->write_packet(s, NULL);
> @@ -902,6 +895,10 @@ int av_write_frame(AVFormatContext *s, AVPacket *pkt)
>         return 1;
>     }
> 
> +    ret = prepare_input_packet(s, pkt);
> +    if (ret < 0)
> +        return ret;
> +
>     ret = do_packet_auto_bsf(s, pkt);
>     if (ret <= 0)
>         return ret;
> @@ -1191,12 +1188,12 @@ int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
> {
>     int ret, flush = 0;
> 
> -    ret = prepare_input_packet(s, pkt);
> -    if (ret < 0)
> -        goto fail;
> -
>     if (pkt) {
> -        AVStream *st = s->streams[pkt->stream_index];
> +        AVStream *st;

Delaying the initialization is not needed as far as I see, so you can keep 
this as is.

> +
> +        ret = prepare_input_packet(s, pkt);
> +        if (ret < 0)
> +            goto fail;
>
>         ret = do_packet_auto_bsf(s, pkt);
>         if (ret == 0)
> @@ -1209,6 +1206,7 @@ int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
>                 pkt->size, av_ts2str(pkt->dts), av_ts2str(pkt->pts));
> 
> #if FF_API_COMPUTE_PKT_FIELDS2 && FF_API_LAVF_AVCTX
> +        st = s->streams[pkt->stream_index];
>         if ((ret = compute_muxer_pkt_fields(s, st, pkt)) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
>             goto fail;
> #endif
> -- 
> 2.20.1

Otherwise LGTM.

Thanks,
Marton
Andreas Rheinhardt April 1, 2020, 3:29 a.m. UTC | #2
Marton Balint:
> 
> 
> On Tue, 31 Mar 2020, Andreas Rheinhardt wrote:
> 
>> It is unnecessary to call prepare_input_packet if there is no packet as
>> it doesn't do anything, except when the currently inactive code guarded
>> by !FF_API_COMPUTE_PKT_FIELDS2 || !FF_API_LAVF_AVCTX becomes active:
>> Then attempting to access pkt->stream_index will crash.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
>> ---
>> This works very well together with Marton's patch #4 [1]:
>> write_packets_common(): The prepare_input_packet() call can be moved
>> into write_packets_common(). Unfortunately, it's not compatible with #5
>> [2] as-is, but I think I have a solution for this.
>>
>> [1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259203.html
>> [2]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259204.html
>>
>> libavformat/mux.c | 22 ++++++++++------------
>> 1 file changed, 10 insertions(+), 12 deletions(-)
>>
>> diff --git a/libavformat/mux.c b/libavformat/mux.c
>> index bfd1bf491b..814d773b9d 100644
>> --- a/libavformat/mux.c
>> +++ b/libavformat/mux.c
>> @@ -771,9 +771,6 @@ static int write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>>
>> static int check_packet(AVFormatContext *s, AVPacket *pkt)
>> {
>> -    if (!pkt)
>> -        return 0;
>> -
>>     if (pkt->stream_index < 0 || pkt->stream_index >= s->nb_streams) {
>>         av_log(s, AV_LOG_ERROR, "Invalid packet stream index: %d\n",
>>                pkt->stream_index);
>> @@ -887,10 +884,6 @@ int av_write_frame(AVFormatContext *s, AVPacket
>> *pkt)
>> {
>>     int ret;
>>
>> -    ret = prepare_input_packet(s, pkt);
>> -    if (ret < 0)
>> -        return ret;
>> -
>>     if (!pkt) {
>>         if (s->oformat->flags & AVFMT_ALLOW_FLUSH) {
>>             ret = s->oformat->write_packet(s, NULL);
>> @@ -902,6 +895,10 @@ int av_write_frame(AVFormatContext *s, AVPacket
>> *pkt)
>>         return 1;
>>     }
>>
>> +    ret = prepare_input_packet(s, pkt);
>> +    if (ret < 0)
>> +        return ret;
>> +
>>     ret = do_packet_auto_bsf(s, pkt);
>>     if (ret <= 0)
>>         return ret;
>> @@ -1191,12 +1188,12 @@ int av_interleaved_write_frame(AVFormatContext
>> *s, AVPacket *pkt)
>> {
>>     int ret, flush = 0;
>>
>> -    ret = prepare_input_packet(s, pkt);
>> -    if (ret < 0)
>> -        goto fail;
>> -
>>     if (pkt) {
>> -        AVStream *st = s->streams[pkt->stream_index];
>> +        AVStream *st;
> 
> Delaying the initialization is not needed as far as I see, so you can
> keep this as is.
> 
Applied with that change. Thanks.

- Andreas
diff mbox series

Patch

diff --git a/libavformat/mux.c b/libavformat/mux.c
index bfd1bf491b..814d773b9d 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -771,9 +771,6 @@  static int write_packet(AVFormatContext *s, AVPacket *pkt)
 
 static int check_packet(AVFormatContext *s, AVPacket *pkt)
 {
-    if (!pkt)
-        return 0;
-
     if (pkt->stream_index < 0 || pkt->stream_index >= s->nb_streams) {
         av_log(s, AV_LOG_ERROR, "Invalid packet stream index: %d\n",
                pkt->stream_index);
@@ -887,10 +884,6 @@  int av_write_frame(AVFormatContext *s, AVPacket *pkt)
 {
     int ret;
 
-    ret = prepare_input_packet(s, pkt);
-    if (ret < 0)
-        return ret;
-
     if (!pkt) {
         if (s->oformat->flags & AVFMT_ALLOW_FLUSH) {
             ret = s->oformat->write_packet(s, NULL);
@@ -902,6 +895,10 @@  int av_write_frame(AVFormatContext *s, AVPacket *pkt)
         return 1;
     }
 
+    ret = prepare_input_packet(s, pkt);
+    if (ret < 0)
+        return ret;
+
     ret = do_packet_auto_bsf(s, pkt);
     if (ret <= 0)
         return ret;
@@ -1191,12 +1188,12 @@  int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, flush = 0;
 
-    ret = prepare_input_packet(s, pkt);
-    if (ret < 0)
-        goto fail;
-
     if (pkt) {
-        AVStream *st = s->streams[pkt->stream_index];
+        AVStream *st;
+
+        ret = prepare_input_packet(s, pkt);
+        if (ret < 0)
+            goto fail;
 
         ret = do_packet_auto_bsf(s, pkt);
         if (ret == 0)
@@ -1209,6 +1206,7 @@  int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
                 pkt->size, av_ts2str(pkt->dts), av_ts2str(pkt->pts));
 
 #if FF_API_COMPUTE_PKT_FIELDS2 && FF_API_LAVF_AVCTX
+        st = s->streams[pkt->stream_index];
         if ((ret = compute_muxer_pkt_fields(s, st, pkt)) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
             goto fail;
 #endif