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

[Paul B Mahol]

On 1/12/13, James Almer <jamrial at gmail.com> wrote:
> On Fri, Jan 11, 2013 at 4:57 PM, Paul B Mahol <onemda at gmail.com> wrote:
>>
>> On 1/11/13, James Almer <jamrial at gmail.com> wrote:
>> > On 08/01/13 3:14 PM, James Almer wrote:
>> >> Write the packet unaltered if found.
>> >>
>> >> Fixes ticket #1917
>> >>
>> >> Signed-off-by: James Almer <jamrial at gmail.com>
>> >> ---
>> >>  libavformat/latmenc.c |    2 +-
>> >>  1 files changed, 1 insertions(+), 1 deletions(-)
>> >>
>> >> diff --git a/libavformat/latmenc.c b/libavformat/latmenc.c
>> >> index 233eab8..b882382 100644
>> >> --- a/libavformat/latmenc.c
>> >> +++ b/libavformat/latmenc.c
>> >> @@ -149,7 +149,7 @@ static int latm_write_packet(AVFormatContext *s,
>> >> AVPacket *pkt)
>> >>      int i, len;
>> >>      uint8_t loas_header[] = "\x56\xe0\x00";
>> >>
>> >> -    if (s->streams[0]->codec->codec_id == AV_CODEC_ID_AAC_LATM)
>> >> +    if (pkt->size > 2 && pkt->data[0] == 0x56 && (pkt->data[1] >> 4)
>> >> ==
>> >> 0xe)
>> >>          return ff_raw_write_packet(s, pkt);
>> >>
>> >>      if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4)
>> >> ==
>> >> 0xf) {
>>
>> Shouldn't  you check exact header and not just part of it?
>>
>> How possible is that valid packet than need header will have first 3 bytes
>> same
>> as loas header?
>
> As Kunhya said, that's the extent of the header.
>
> I added a check to compare the size of the packet with the size
> reported at the end
> of the LOAS header (last 13 bits).
> That should make sure only actual LOAS packets pass the entire set of
> checks.
>
> Regards.
>

probably ok