segmentation of MP4 video over RTP

1
votes

I'm trying to understand how a MP4 video is going to be segmented over RTP in online streaming (it's coded with the H.264 codec). There are some tools like FFMPEG or MP4box, or we can use the ISO format itself [moov, pair of moof and mdat] for streaming. What I want to know is how these tools will segment mdat part of video? Will they separate all the units (a group of video and audio frames) of the MP4 video and make them into one segment with related moov part or they do it in some other way?

Or do they use H264 streaming and NAL units for streaming?

I want to know how it works.

1
videovideo-streamingmp4h.264
MP4 is not sent over RTP. Its is repackaged from MP4 to RTP and (possibly) back again on the other side. – szatmary
so it will be used in DASH or HLS streaming? for RTP i cant use ffmpeg? – lighting
What? Dash and HLS and RTP are competing technologies. You can convert between them but you don't0 use one on top of the other. RTP doesn't use segments. Segments are only using in HTTP protocols (HLS and DASH) – szatmary
So RTP will send the whole file after adding headers? – lighting
No, there is no "file" once its converted to RTP, its just a series for frames. RTP is not FTP. – szatmary

1 Answers

1
votes

Typically, the video streaming flow goes like this:

Capture Video--> Encode-->                                     -->Decode-->Display
                            Mux--> Transmit--> Receive-->De-Mux  
Capture Audio--> Encode-->                                     -->Decode-->Display

So, basically in your case, ffmpeg takes NAL units from H.264 and muxes it with encoded audio bitstream and transmits together.