eflvmux

eflvmux is an extension to the flvmux, capable of multiplexing multiple tracks and signalling advanced codecs in FOURCC format as per Enhanced RTMP (V2) specification.

Two types of sink pads can be requested from eflvmux

1. audio/video - for create a default track and can be used to stream in the legacy or extended FLV format. The format can be selected using the flv-track-mode pad property. See flv-track-mode

2. audio_%u/video_%u - for creating multiple tracks in extended FLV format of multitrack type, each with a unique non-zero track ID. The track ID will be same as the pad index.

It is important to specify the right pad template (preferably with specific pad index in case of _%u type pads) while linking pads using gst_element_link_pads or _parse_launch. Failing to specify the pad template can result streaming in the wrong FLV format.

Note: Since we use pad index as the track id and a track with id 0 can be created only through the audio/video pads, requesting a audio_0 or video_0 is not allowed.

Example launch line saving 2 audio and 2 video tracks to a FLV file

gst-launch-1.0 eflvmux name=mux audio::flv-track-mode=multitrack video::flv-track-mode=non-multitrack  ! filesink location=$HOME/Videos/test_eflv_non.flv \
   audiotestsrc  wave=ticks ! audio/x-raw,rate=44100,format=S16LE,channels=2 ! fdkaacenc ! mux.audio \
   audiotestsrc  wave=white-noise  ! audio/x-raw,rate=44100,format=S16LE,channels=2 !  fdkaacenc ! mux.audio_2  \
   videotestsrc ! videoconvert ! timeoverlay ! x264enc tune=zerolatency key-int-max=30 ! h264parse ! mux.video   \
   videotestsrc ! videoconvert ! timeoverlay ! x265enc ! h265parse ! mux.video_2

The pipeline creates - the default audio track from the audio pad in multitrack eFLV format with track id 0 - additional audio track from the audio_1 pad in the multitrack eFLV format with track id 1 - the default video track from the video pad in non-mulitrack eFLV format so it won't have any track id - additional video track from the video_1 pad in the multitrack eFLV format with track id 1

To play the above file using ffplay (FFmpeg version 8 or greater)

ffplay $HOME/Videos/test_eflv_non.flv

(switch the video tracks using v and audio tracks with a keys)

Example launch line for streaming 2 audio tracks to Twitch

gst-launch-1.0 videotestsrc pattern=ball ! 'video/x-raw,format=I420,width=1280,height=720,framerate=30/1' ! \
   timeoverlay ! videoconvert ! x264enc tune=zerolatency key-int-max=30 ! h264parse ! eflvmux name=mux ! \
   rtmp2sink location="rtmp://ingest.global-contribute.live-video.net/app/$STREAM_KEY" \
   audiotestsrc wave=ticks ! fdkaacenc ! mux.audio \
   audiotestsrc !  fdkaacenc ! mux.audio_1