[FFmpeg-cvslog] avformat/mpegts: fix max_packet_size in mpegts payload parsing

[Marton Balint]

ffmpeg | branch: master | Marton Balint <cus at passwd.hu> | Tue Sep 21 22:30:55 2021 +0200| [9420f7e09560d82ebdb96ddc6724a734f4fe0b95] | committer: Marton Balint

avformat/mpegts: fix max_packet_size in mpegts payload parsing

The maximum allowed useful PES payload data was set to PES_packet_length, but
it is in fact smaller by the length of the PES header.

This changes how corrupt streams are packetized:
- If PES header length is bigger than PES_packet_length then the PES packet
  payload will be handled as an unbound packet
- PES packets with payload across multiple MPEGTS packets will always be
  splitted if with the next chunk of data the payload should exceed
  PES_packet_length, previously a PES_header_length amount of excess was
  allowed.

Fixes ticket #9355.

Signed-off-by: Marton Balint <cus at passwd.hu>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9420f7e09560d82ebdb96ddc6724a734f4fe0b95
---

 libavformat/mpegts.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index d4f5355d97..9a6bbb1c93 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -1358,8 +1358,8 @@ skip:
         case MPEGTS_PAYLOAD:
             do {
                 int max_packet_size = MAX_PES_PAYLOAD;
-                if (pes->PES_packet_length)
-                    max_packet_size = pes->PES_packet_length;
+                if (pes->PES_packet_length && pes->PES_packet_length + PES_START_SIZE > pes->pes_header_size)
+                    max_packet_size = pes->PES_packet_length + PES_START_SIZE - pes->pes_header_size;
 
                 if (pes->data_index > 0 &&
                     pes->data_index + buf_size > max_packet_size) {