[FFmpeg-devel] Adding Sequence number to frames

[XUE MINGQIANG]

Hi All,

I am very new to both streaming and ffmpeg.

Basically, I want to achieve the following task:

I have a LAN and a RTSP video source machine. I want to do some CV
task e.g. face detection, on another machine, and display the result
in the form of continuous original video stream (with detected faces
in rectangles) on a client machine in the same LAN. I want to have the
following design:

Ideally, each frame of the video stream is labelled with a unique
sequence number. On the CV-task machine, I select the frames that need
for face detection, record down its sequence number and coordinates of
detected faces. Then I forward the (sequence number, coordinates)
pairs to the client machine. The client machine runs an RTSP client
and receive stream from the source, but instead of playing the stream
directly, it temporally stores the received frame in a buffer until it
receives the (sequence number, coordinates) from the CV-task machine.
The sequence number is used to find the frame on which the rectangles
for faces should be put onto. Once the rectangles are added to the
right frames, the video is read from the buffer and played.

My questions are as follows:

1. Does each frame of a video stream, e.g. the H264 stream contain an
unique identifier? If so, how to get this unique identifier?

2. If such unique identifier does not exist, I am thinking to add a
proxy machine between the video source and the other machines in the
network. The proxy server basically read rtsp stream from the source,
and add unique sequence number to each extracted frame, and then it
re-stream the video to the other machines. So in this way, each
machine in the network can see frames with unique IDs.

Since, I am quite new to video streaming, my questions could be naive.
Please help me.

I feel both ffmpeg and live555 need to be used. How about ffserver?
what's the difference between ffserver and live555 proxy server?

Thank you.

Regards
Mitchell