[FFmpeg-devel] Fix for PES packets with too much padding

[Michael Niedermayer]

On Tue, Aug 03, 2021 at 10:07:34AM -0400, Sergio M. Ammirata, Ph.D. wrote:
> PES packet with too much padding trigger unlimited error
> messages "PES packet size mismatch" because the code that
> corrects the length is wrong.
> Here is a sample file: http://99.93.62.129/smpte2038.ts
> PID 300 is the one triggering the errors.
> I am attaching a patch that fixes the problem.
> 

>  mpegts.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 8f8c73a5e78d7c740958054764defa3571979fc4  0001-Fix-setting-the-correct-size-for-PES-packets-with-to.patch
> From 3a2760d42b38023c73f9a3ab18de01a44526dbc9 Mon Sep 17 00:00:00 2001
> From: Sergio Ammirata <sergio at ammirata.net>
> Date: Tue, 3 Aug 2021 13:43:44 +0000
> Subject: [PATCH] Fix setting the correct size for PES packets with too much
>  padding
> 
> ---
>  libavformat/mpegts.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> index 640c9afa5d..40439c26c0 100644
> --- a/libavformat/mpegts.c
> +++ b/libavformat/mpegts.c
> @@ -1355,7 +1355,7 @@ skip:
>                             buf_size > pes->total_size) {
>                      // pes packet size is < ts size packet and pes data is padded with 0xff
>                      // not sure if this is legal in ts but see issue #2392
> -                    buf_size = pes->total_size;
> +                    buf_size = PES_START_SIZE + pes->total_size - pes->pes_header_size;
>                  }
>                  memcpy(pes->buffer->data + pes->data_index, p, buf_size);
>                  pes->data_index += buf_size;

This causes segfaults

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have often repented speaking, but never of holding my tongue.
-- Xenocrates
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