On Thu, Nov 24, 2016 at 01:37:17AM +0100, Andreas Cadhalpun wrote:
> On 23.11.2016 03:26, Michael Niedermayer wrote:
> > On Fri, Nov 04, 2016 at 10:28:20PM +0100, Andreas Cadhalpun wrote:
> >> Otherwise the codec context and codecpar might disagree on the codec id,
> >> triggering asserts in av_parser_parse2.
> >>
> >> Signed-off-by: Andreas Cadhalpun <andreas.cadhal...@googlemail.com>
> >> ---
> >> libavformat/flvdec.c | 16 ++++++++++++----
> >> 1 file changed, 12 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> >> index e53c345..4ba7fc8 100644
> >> --- a/libavformat/flvdec.c
> >> +++ b/libavformat/flvdec.c
> >> @@ -289,7 +289,9 @@ static int flv_same_video_codec(AVCodecParameters
> >> *vpar, int flags)
> >> static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream,
> >> int flv_codecid, int read)
> >> {
> >> + int ret = 0;
> >> AVCodecParameters *par = vstream->codecpar;
> >> + enum AVCodecID old_codec_id = vstream->codecpar->codec_id;
> >> switch (flv_codecid) {
> >> case FLV_CODECID_H263:
> >> par->codec_id = AV_CODEC_ID_FLV1;
> >> @@ -317,20 +319,26 @@ static int flv_set_video_codec(AVFormatContext *s,
> >> AVStream *vstream,
> >> else
> >> avio_skip(s->pb, 1);
> >> }
> >> - return 1; // 1 byte body size adjustment for flv_read_packet()
> >> + ret = 1; // 1 byte body size adjustment for flv_read_packet()
> >> + break;
> >> case FLV_CODECID_H264:
> >> par->codec_id = AV_CODEC_ID_H264;
> >> vstream->need_parsing = AVSTREAM_PARSE_HEADERS;
> >> - return 3; // not 4, reading packet type will consume one byte
> >> + ret = 3; // not 4, reading packet type will consume one byte
> >> + break;
> >> case FLV_CODECID_MPEG4:
> >> par->codec_id = AV_CODEC_ID_MPEG4;
> >> - return 3;
> >> + ret = 3;
> >> + break;
> >> default:
> >> avpriv_request_sample(s, "Video codec (%x)", flv_codecid);
> >> par->codec_tag = flv_codecid;
> >> }
> >>
> >> - return 0;
> >> + if (par->codec_id != old_codec_id)
> >> + vstream->internal->need_context_update = 1;
> >
> > If this occurs only for fuzzed samples then rejecting the change
> > with a request for a sample seems better
> >
> > changing teh codec_id midstream like this could, seems problematic
> > changing at at header time might be ok if that works better than not
> > changing it for some real sample
>
> This happens for almost every file, because at the beginning the codec_id
> is AV_CODEC_ID_NONE. However, usually need_context_update is already
> set from avformat_new_stream, so a change can be rejected, if this
> is not the case. Patch doing that attached.the code i tested prviously checked for AV_CODEC_ID_NONE but this is probably ok too thx 8...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The worst form of inequality is to try to make unequal things equal. -- Aristotle
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