Looping one or multiple VoD files into a never ending live stream. Using Livepeer as an example.

loop.md

Looping VoD

This is a quick tutorial for looping a VoD file as a live stream, using ffmpeg.

Step 1: convert source video to .ts file

In order to loop a video file, you need to convert it into the .ts format. Use this command:

ffmpeg -i input.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts output.ts

Step 2: Loop the .ts video with ffmpeg

In order to loop the video, you will need to run this ffmpeg command in a bash script. This command ensures the timestamp properly increments during looping. Be sure to put in your own stream key.

#!/bin/bash

function mixem {
  while : ; do cat output.ts ; done
}

mixem | ffmpeg -f mpegts -re -i - -c:v h264 -b:v 2m -x264opts "keyint=50:min-keyint=50:no-scenecut" -c:a aac -preset veryfast -g 50 -map 0:v -map 0:a -f flv rtmp://rtmp.livepeer.com/live/{stream-key}

Optional: concatinate multiple source files

There are many tools available to concatinate multiple video files. One option is to use the follow commands:

cat input1.ts input2.ts input3.ts > all_input.ts

ffmpeg -i all_input.ts -vf scale=w=1280:h=720:force_original_aspect_ratio=decrease -c:a aac -ar 48000 -b:a 128k -c:v h264 -profile:v main -crf 20 -g 50 -keyint_min 50 -sc_threshold 0 -b:v 2500k -maxrate 2675k -bufsize 3750k -f mpegts all_output.ts

These commands makes sure the files are merged with uniform settings like resolution, frame rate, etc. The output can be put into the looping script.