Combine mp4 video and a RTMP stream into 1 RTMP output stream via ffmpeg

Question

I need a ffmpeg command to first feed a mp4 video into a RTMP output stream, then followed by a RTMP input subsequently; what should be the parameters to get it working?

Answer 1

You can do something like this:

ffmpeg
-i intro.mp4
-i rtmp://second-input-server:port/input-id
-filter_complex "concat=n=2:v=1:a=1[merged_video][merged_audio]"
-map [merged_video] -map [merged_audio] -f flv rtmp://final-output:port/merged

• We are taking two inputs, one from a local file (intro.mp4) and one using an rtmp address (rtmp://second-input-server:port/input-id).
• We are using the concat filter here, specifying that it has 2 segments to concant (n=2), each segment having 1 video (v=1) and 1 audio stream (a=1).
• We are labelling the concatted streams as merged_video and merged_audio, and muxing them into flv format, before sending that to the output rtmp server (rtmp://final-output:port/merged).

This assumes that you have the two inputs having same number of streams (1 video and 1 audio), same frame rate, same dimensions etc. If you don't, you may need to add additional filters (e.g. scale, fps) and stream selectors (e.g. [0:v:0], [1:a:1]) above to first make the two streams have the same characteristics, before feeding those to the concat filter.