[FFmpeg-devel] [PATCH] latmenc: Check for LOAS sync word

[Paul B Mahol]

On 1/16/13, James Almer <jamrial at gmail.com> wrote:
> On 15/01/13 10:34 PM, Michael Niedermayer wrote:
>> you can check extradata
>> as a sideeffect it would fix the crash
>> with the right (well wrong) data the current patch not fix the crash
>
> How about the attached patch? (It still needs reindentation)
> If there's no extradata then the packet is either LOAS or ADTS, and it
> should be
> used if it's the former or discarded if it's anything else.
>
> This also prevents potential misdetection of raw packets as ADTS packets,
> since
> the check was on the first 3 bytes as well and without checking if there was
> any
> extradata available.
>
> Regards.
>

Please use git send-mail.

> From dc95954687b24faf19284fa39d5cb34ce5863741 Mon Sep 17 00:00:00 2001
> From: James Almer <jamrial at gmail.com>
> Date: Wed, 16 Jan 2013 05:21:55 -0300
> Subject: [PATCH] latmenc: Check for LOAS sync word
>
> Write the packet unaltered if found.
>
> Fixes ticket #1917
>
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavformat/latmenc.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/latmenc.c b/libavformat/latmenc.c
> index 233eab8..d6bdf62 100644
> --- a/libavformat/latmenc.c
> +++ b/libavformat/latmenc.c
> @@ -152,8 +152,14 @@ static int latm_write_packet(AVFormatContext *s, AVPacket *pkt)
>      if (s->streams[0]->codec->codec_id == AV_CODEC_ID_AAC_LATM)
>          return ff_raw_write_packet(s, pkt);
>
> -    if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4) == 0xf) {
> +    if (!s->streams[0]->codec->extradata) {

You do not check if extradata have anything valid?

> +        if (pkt->size > 2 && pkt->data[0] == 0x56 && (pkt->data[1] >> 4) == 0xe &&
> +            (AV_RB16(pkt->data + 1) & 0x1FFF) + 3 == pkt->size)
> +            return ff_raw_write_packet(s, pkt);
> +
> +    if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4) == 0xf)
>          av_log(s, AV_LOG_ERROR, "ADTS header detected - ADTS will not be incorrectly muxed into LATM\n");

This message is really strange.

> +
>          return AVERROR_INVALIDDATA;
>      }
>      if (pkt->size > 0x1fff)
> --
> 1.8.0.msysgit.0
>