ffmpeg :: avcodec_encode_video设置PTS h264 [英] ffmpeg::avcodec_encode_video setting PTS h264

问题描述

我想使用libavcodec将视频编码为H264

ffmpeg :: avcodec_encode_video（codec，output，size，avframe） / code>

返回一个错误，我没有正确设置avframe-> pts值。

我试过设置它到0,1，AV_NOPTS_VALUE和90khz * framenumber，但仍然得到错误非严格单调的PTS

ffmpeg.c示例使用ffmpeg :: av_rescale_q（）设置packet.pts，但这只有在编码帧后才会调用！

与MP4V编解码器我有同样的问题，解决它通过计算pts之前调用avcodec_encode_video（）。如下：

  //计算PTS：（1 / FPS）*采样率*帧数
 // sample速率90KHz是用于h.264在30 fps 
 picture-> pts =（1.0 / 30）* 90 * frame_count; 
 out_size = avcodec_encode_video（c，video_outbuf，video_outbuf_size，picture）; 
  

解决方案从此帮助博客帖子

（注意：更改采样率为khz，以hz表示长帧之间，可能需要使用这个值 - 不是一个视频编码专家在这里，只是想要的东西，工作，这样做）

I'm trying to encode video as H264 using libavcodec

ffmpeg::avcodec_encode_video(codec,output,size,avframe);

returns an error that I don't have the avframe->pts value set correctly.
I have tried setting it to 0,1, AV_NOPTS_VALUE and 90khz * framenumber but still get the error non-strictly-monotonic PTS

The ffmpeg.c example sets the packet.pts with ffmpeg::av_rescale_q() but this is only called after you have encoded the frame !

When used with the MP4V codec the avcodec_encode_video() sets the pts value correctly itself.

解决方案

I had the same problem, solved it by calculating pts before calling avcodec_encode_video as follows:

//Calculate PTS: (1 / FPS) * sample rate * frame number
//sample rate 90KHz is for h.264 at 30 fps
picture->pts = (1.0 / 30) * 90 * frame_count;
out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);

Solution stolen from this helpful blog post

(Note: Changed sample rate to khz, expressed in hz was far too long between frames, may need to play with this value - not a video encoding expert here, just wanted something that worked and this did)

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