用ffmpeg解码h264 rtsp并分离AVCodecContext [英] Decode h264 rtsp with ffmpeg and separated AVCodecContext

问题描述

我需要一些关于decodein rtsp视频流的帮助。
我从AXIS IP摄像头获取。我使用ffmpeg库。
必须分别创建AVCodecContext，而不是从AVFormatContext-> streams [...] - > codec;

I need some help with decodein rtsp stream of video. I get it from AXIS IP-camera. I use ffmpeg library for it. It is neccessary to create AVCodecContext separately, not from AVFormatContext->streams[...]->codec;

所以我创建AVCodec，AVCOdecContext和try要启动它们。

So i create AVCodec, AVCOdecContext and try to init them.

AVCodec *codec=avcodec_find_decoder(codec_id);
if(!codec)
{
    qDebug()<<"FFMPEG failed to create codec"<<codec_id;
    return false; //-->
}

AVCodecContext *context=avcodec_alloc_context3(codec);
if(!context)
{
    qDebug()<<"FFMPEG failed to allocate codec context";
    return false; //-->
}
avcodec_open2(context, codec, NULL);

然后在应用程序的主循环中，我获取帧数据并尝试解码：

Then in main loop of application, i get frames data and try to decode:

_preallocatedFrame = avcodec_alloc_frame();
avcodec_decode_video2(_context, _preallocatedFrame, &got_picture, &_packet);

这里我在控制台中收到很多消息：

And here I get lots of messages in console:

[h264 @ 1f177720] decode_slice_header error
[h264 @ 1f177720] no frame!
[h264 @ 1f177720] non-existing PPS 0 referenced
[h264 @ 1f177720] decode_slice_header error
[h264 @ 1f177720] no frame!
[h264 @ 1f177720] non-existing PPS 0 referenced
[h264 @ 1f177720] decode_slice_header error
[h264 @ 1f177720] no frame!
[h264 @ 1f177720] non-existing PPS 0 referenced
[h264 @ 1f177720] decode_slice_header error
[h264 @ 1f177720] no frame!
[h264 @ 1f177720] non-existing PPS 0 referenced
[h264 @ 1f177720] decode_slice_header error
[h264 @ 1f177720] no frame!
[h264 @ 1f177720] non-existing PPS 0 referenced
[h264 @ 1f177720] decode_slice_header error
[h264 @ 1f177720] no frame!

你能给我一些建议，如何初始化AVCodecContext或其他什么来做到正确吗？ >

Can you advice me something, how to init AVCodecContext or something else to do it correct?

推荐答案

您需要执行更多的工作。
如果要解码h.264流，您需要通过解码器的sps pps数据。
此数据可以在rtp流本身找到请参阅

You need to perform some more work. if you want to decode h.264 stream you need to pass the decoder the "sps pps" data. This data can be found on the rtp stream itself see

或SDP中的rtsp协商。
在您成功为解码器提供此数据后，解码就可以正常工作。

or in th rtsp negotiation in the SDP. after you successfully feed the decoder with this data, the decoding should work.

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