Encoding FFMPEG to MPEG-DASH – or WebM with Keyframe Clusters – for MediaSource API

Question

I'm currently sending a video stream to Chrome, to play via the MediaSource API.

As I understand it, MediaSource only supports MP4 files encoded with MPEG-DASH, or WebM files that have clusters beginning with keyframes (otherwise it raises the error: Media segment did not begin with keyframe).

Is there any way to encode in MPEG-DASH or keyframed WebM formats with FFMPEG in real-time?

Edit:

I just tried it with ffmpeg ... -f webm -vcodec vp8 -g 1 so that every frame is a keyframe. Not the ideal solution. It does work with MediaStream now though. Any way to sync up the segments with the keyframes in WebM so not every frame needs to be a keyframe?

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Reference Questions on WebM / MP4 and MediaSource:

Media Source Api not working for a custom webm file (Chrome Version 23.0.1271.97 m)

MediaSource API and mp4

Answer 1

At the moment FFMPEG does not support DASH encoding. You can segment with FFMPEG (https://www.ffmpeg.org/ffmpeg-formats.html#segment_002c-stream_005fsegment_002c-ssegment), but I recommend combining FFMPEG and MP4Box. Use FFMPEG to transcode your live video, and then MP4Box to segment and create the .mpd index.

MP4Box is a part of GPAC (http://gpac.wp.mines-telecom.fr/).

Here is an example using h264:

ffmpeg -threads 4 -f v4l2 -i  /dev/video0 -acodec libfaac -ar 44100 -ab 128k -ac 2 -vcodec libx264 -r 30 -s 1280x720  -f mp4 -y "$movie" > temp1.mp4 && MP4Box -dash 10000 -frag 1000 -rap "$movie"

If you need VP8 (WebM), use: -vcodec libvpx and -f webm or -f ts.