[英]Saving frames from a network camera (RTSP) to a mp4 file
I am quite confused about how to save a video stream into a mp4 file. 我对如何将视频流保存到mp4文件中感到非常困惑。 I am using ffmpeg. 我正在使用ffmpeg。 Let me explain the problem: 让我解释一下这个问题:
The problem is that the resulting mp4 video has artifacts if I try to watch it using VLC, Windows Media Player, or another one. 问题是,如果我尝试使用VLC,Windows Media Player或其他播放器观看最终的mp4视频,则该视频会带有伪影。
I have also realized that the pts of that packets are not continuous, while dts are continuous. 我还意识到,这些数据包的pt是不连续的,而dts是连续的。 I know about B frames, but is this a problem in my case? 我知道B帧,但是这对我来说是个问题吗?
// Prepare the output
AVFormatContext* oc = avformat_alloc_context();
oc->oformat = av_guess_format(NULL, "video.mp4", NULL);
// Must write header, packets, and trailing
avio_open2(&oc->pb, "video.mp4", AVIO_FLAG_WRITE, NULL, NULL);
// Write header
AVStream* stream = avformat_new_stream(oc, (AVCodec*) context->streams[video_stream_index]->codec->codec);
avcodec_copy_context(stream->codec, context->streams[video_stream_index]->codec);
stream->sample_aspect_ratio = context->streams[video_stream_index]->codec->sample_aspect_ratio;
avformat_write_header(oc, NULL);
// FOR EACH FRAME...
... av_write_frame(oc, circular[k]); ...
// Write trailer and close the file
av_write_trailer(oc);
avcodec_close(stream->codec);
avio_close(oc->pb);
avformat_free_context(oc);
Thank you so much, 非常感谢,
First: when you work with the camera, it is better to work through an RTP over TCP (TCP as transport protocol). 第一:使用相机时,最好通过TCP上的RTP(TCP作为传输协议)进行操作。 To enable this feature: 要启用此功能:
AVDictionary *ifmtdict;
av_dict_set(&ifmtdict, "rtsp_transport", "tcp", 0);
...
avformat_open_input (..., &ifmtdict);
Second: After the packets start coming, wait for the first keyframe and start to write to the file from this moment. 第二:数据包开始发送之后,请等待第一个关键帧并从此刻开始写入文件。
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