将RTP vp8有效负载数据包保存到.webm文件

Question

I have saved a video call to a .pcap file with Wireshark, and I want to acquire the video from RTP packets. RTP packets payload type is vp8 , I could find out the vp8 RTP packets by using libpcap library in C++. Then I saved the contents of all RTP vp8 packets to a file. But i can not convert this raw vp8 data to .mp4 by using ffmpeg. ffmpeg gives error during conversion. ffmpeg conversion error : Invalid data found when processing input

What are the steps to get .mp4 or .webm video file from vp8 RTP packets?

Edit : I could get raw VP8 data excluding VP8 payload descriptor, payload header and keyframe header. Then I added ivf header and frame header for each vp8 raw frame, according to ivf document IVF Document

But When I want to convert my ivf file (output1) to output1.mp4 by using ffmpeg

ffmpeg -i output1 -c:v vp8 output1.mp4

I get errors

Answer 1

JanusGateway is having functionality to convert RTP (VP8/VP9/H264/Opus) to (webm/mp4). It will just encode RTP to corresponding container(webm/mp4/opus), no transcoder is included.

You can use ffmpeg to transcode it to any other format.

In brief, janus will store RTP packets in a file by adding a prefix header in each packet. Then we can use post processor to convert vp8 RTP packets to webm.

https://github.com/meetecho/janus-gateway/blob/master/postprocessing/pp-webm.c

You can see the live demo & Documentation .