[Live-devel] "no frame!"

[Jeff Shanab]

You may be doing a bit more work than is necessary. Most H264 streams have the SPS and PPS embedded periodically.

Here is my setup, note the extradata is set to NULL and size set to 0. This you need to do then on decode of the first frame liavcode fills in the rest of the context.

pCodec_ = avcodec_find_decoder(CODEC_ID_H264);
                           if (!pCodecCtx_) {
                                  throw std::exception("[CH264Filter]: Can't allocate pCodecCtx_!");
                           }
                           pCodecCtx_ = avcodec_alloc_context();


                           pCodecCtx_->skip_frame            = AVDISCARD_DEFAULT;
                           pCodecCtx_->skip_idct             = AVDISCARD_DEFAULT;
                           pCodecCtx_->skip_loop_filter    = AVDISCARD_DEFAULT;

                           pCodecCtx_->error_concealment   = FF_EC_GUESS_MVS | FF_EC_DEBLOCK ;


                           pCodecCtx_->workaround_bugs     = FF_BUG_AUTODETECT | FF_BUG_MS;
                           pCodecCtx_->strict_std_compliance = FF_COMPLIANCE_NORMAL | FF_COMPLIANCE_UNOFFICIAL;
                           pCodecCtx_->error_recognition   = FF_ER_CAREFUL;
                           pCodecCtx_->codec_type            = CODEC_TYPE_VIDEO;
                           pCodecCtx_->codec_id            = CODEC_ID_H264;
                           pCodecCtx_->codec_tag             =  MKTAG('H', '2', '6', '4');


                           pCodecCtx_->extradata             = NULL;
                           pCodecCtx_->extradata_size        = 0;


                           res = avcodec_open(pCodecCtx_, pCodec_);
                           if(res < 0)
                                  throw std::exception("Can't open video codec!");

I actually create the SPS and PPS from the spprops and insert them into the stream if the encoder does not do already do that for me. (Like VLC does when capturing)


From: live-devel-bounces at ns.live555.com [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Jer Morrill
Sent: Wednesday, January 11, 2012 6:51 PM
To: LIVE555 Streaming Media - development & use
Subject: Re: [Live-devel] "no frame!"

I just implemented an custom H264 source and decoder with FFMPEG.  Here's how I did it (in concept):


1.)    Get the subsession->fmtp_configuration() string

2.)    Do something like this with H264VideoRTPSource.hh included - "auto records = parseSPropParameters(fmtp_configuration, recordCount);"

3.)    Each of the returned records from step 2, prepend a 0x00000001

4.)    Each sample you send to FFMPEG, prepend each of your records from step 3 to your sample buffer

I'm not sure if I'm telling you incorrect information, but this worked for me!

-Jer

From: live-devel-bounces at ns.live555.com<mailto:live-devel-bounces at ns.live555.com> [mailto:live-devel-bounces at ns.live555.com]<mailto:[mailto:live-devel-bounces at ns.live555.com]> On Behalf Of Menne, Neil
Sent: Wednesday, January 11, 2012 2:54 PM
To: live-devel at lists.live555.com<mailto:live-devel at lists.live555.com>
Subject: [Live-devel] "no frame!"

I'm working on my Live555/FFmpeg video player, and I ran into an interesting problem that has kept me stumped for several days. I am taking the buffer that is delivered to my MediaSink (like the example in testRTSPClient), and I am passing the buffer and the size to FFmpeg to decode. It says that there is "no frame!" I'm stumped as to why that is the case when I'm taking the buffer after the "afterGettingFrame" function is called. I was wondering if there was something else that must be done to that buffer for it to be a true frame that can be decoded.

My first guess is that the decoder needs more information which brings me to my next question: the SDP description that I'm pulling down doesn't contain the width/height, so I'm guessing I need to pull that out of the sprop_parameter_sets; is this the case?

My second guess is that there is no frame separator; I noticed that in one particular file: H264VideoFileSink they prepend a 0x00000001 along with the sprop_parameters. Is this a potential problem?

Video is not my expertise, so I'm spending most days reading anything/everything on these problems, but this one's got me stuck.

-Neil

P.S. My video is an H.264 video stream



________________________________
No virus found in this message.
Checked by AVG - www.avg.com<http://www.avg.com>
Version: 2012.0.1901 / Virus Database: 2109/4737 - Release Date: 01/11/12
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.live555.com/pipermail/live-devel/attachments/20120112/4d2b2e73/attachment.html>