[FFmpeg-devel] [PATCH]refine the flv tagtype read for check as spec

Michael Niedermayer michaelni at gmx.at
Thu Sep 4 14:53:58 CEST 2014


On Thu, Sep 04, 2014 at 08:23:19PM +0800, Steven Liu wrote:
> from the flv spec, the flvtag define the tagtype as one byte,
> the spec desc is:
> Reserved  UB[2] Reserved for FMS, should be 0
> Filter    UB[1] Indicates if packets are filtered.
>                 0 = No pre-processing required.
>                 1 = Pre-processing (such as decryption) of the packet is
>                     required before it can be rendered.
>                     Shall be 0 in unencrypted files, and 1 for encrypted
> tags.
>                     See Annex F. FLV Encryption for the use of filters.
> TagType   UB[5] Type of contents in this tag. The following types are
>                 defined:
>                         8 = audio
>                         9 = video
>                         18 = script data
> 
> Signed-off-by: Steven Liu <qi.liu at chinacache.com>
> ---
>  libavformat/flvdec.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> index 8d9ed8b..a0550b4 100644
> --- a/libavformat/flvdec.c
> +++ b/libavformat/flvdec.c
> @@ -777,7 +777,7 @@ static int flv_read_packet(
> AVFormatContext *s, AVPacket *pkt)
>      /* pkt size is repeated at end. skip it */
>      for (;; avio_skip(s->pb, 4)) {
>          pos  = avio_tell(s->pb);
> -        type = avio_r8(s->pb);
> +        type = (avio_r8(s->pb) & 0x1F);
>          size = avio_rb24(s->pb);
>          dts  = avio_rb24(s->pb);
>          dts |= avio_r8(s->pb) << 24;

patch applied

thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In fact, the RIAA has been known to suggest that students drop out
of college or go to community college in order to be able to afford
settlements. -- The RIAA
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