[gst-devel] __Re:_re：_Re:_how_to_use_qtdemux_to_demux_h264_stream_from_MP4?

[Edward Hervey]

Hi,

  I forgot to mention that this patch doesn't solve your problem, but
changes some behaviour in qtdemux. The real question was whether it
broke the behaviour of your decoder or not, since with the existing
h264 decoders it doesn't.

  Hoping somebody more knowledgeable about h264 will help solve your problem,

    Edward

On 3/28/07, jp_liu <jp_liu at astrocom.cn> wrote:
>
>
> Edward Hervey, Hello
>
> Thanks for your reply.
> But I think you have misunderstood .
> My problem is my decoder(buy from 3rd party) can not decode the frame
> without sps,pps and nal unit(Bytestream).  I must covert the frames to the
> Byte-stream frames, such as add sps pps at first frame , add start code at
> each nal unit.... so your patch can not solve my problem,but anyway, thanks.
>
> jp_liu, jp_liu at astrocom.cn
> 2007-03-28
>
> ----- Receiving the following content -----
> From: Edward Hervey
> Receiver: jp_liu
> Time: 2007-03-27, 17:18:32
> Subject:
> Re:_[gst-devel]_Re:_[gst-devel]re：_Re:_how_to_use_qtdemux_to_demux_h264_stream_from_MP4?
>
>
>
>
>
> Hi,
>
>   Could you also try applying the following patch fixing qtdemux so
> that it outputs h264 buffers with pts instead of dts. If you are
> making a software decoder you shouldn't need the dts.
>   the patch and explanations are here :
> http://bugzilla.gnome.org/show_bug.cgi?id=423283
>
>     Edward
>
> On 3/26/07, jp_liu <jp_liu at astrocom.cn> wrote:
> >
> >
> > zhangfei gao, Hello
> >
> > My h264 decoder support say that:
> > I believe MP4 uses the NAL format (Need to confirm) and hence doesn't have
> > the NAL Start codes. One needs to convert that to bytstream format because
> > our decoders support only byte-stream format. Also one needs to do this
> > while demuxing it from MP4 otherwise the information various slice
> positions
> > would be lost.
> >
> > So, How should I do?
> >
> > jp_liu, jp_liu at astrocom.cn
> > 2007-03-26
> >
> > ----- Receiving the following content -----
> > From: zhangfei gao
> > Receiver: gstreamer-devel
> > Time: 2007-03-22, 21:24:01
> > Subject: [gst-devel]re： Re: how to use qtdemux to demux h264 stream from
> > MP4?
> >
> >
> >
> >
> >
> >
> > hi, jp_liu
> >
> > "h264.c" in ffmpeg has useful information of how to parse "codec_data"
> which
> > get set_caps.
> > "codec_data" has all the nal_length, sps data and pps data.
> >
> > Thanks
> > Jan Schmidt <thaytan at noraisin.net> 写道：
> > jp_liu wrote:
> > > Hello, gstreamer-devel
> > >
> > > How to use qtdemux to demux h264 stream from MP4?
> > > The demuxed h264 stream looks have no startcodes before every NAL
> > > Unit. So, Some key information ( such as: SPS PPS ....) is missed. It
> > > caused my H264 decoder can not decode the frame which demuxed by qtdemux
> .
> > > How can I solve this problem?
> > >
> >
> > I think the information your decoder is looking for is the stuff
> > provided by the 'codec_data' in the caps. This is the header information
> > that quicktime stores and provides separately from the actual data stream.
> >
> > Regards,
> > Jan.
> >
> >
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> --
> Edward Hervey
> Multimedia editing developer / Fluendo S.A.
> http://www.pitivi.org/
>


-- 
Edward Hervey
Multimedia editing developer / Fluendo S.A.
http://www.pitivi.org/