CODEWITHSUNDEEP
videoavconvtranscode
alexs973
alexs973

Reputation: 183

Use avconv to live transcode video file based on bandwidth

I have an Apache web server where I have several videos. I also have end users that log into my server and stream those videos. The problem is some of these videos are very large and sometimes the user's bandwidth can't support that.

Here's what I want to do: When the user streams the video, I want that video to be transcoding in real time based on their available bandwidth. If their bandwidth is low, lower the fps or bps. If it's higher, raise it etc.

How can I do this?

Upvotes: 0

Views: 112

Answers (1)

Mick
Mick

Reputation: 25481

While the real time transcoding approach is possible, the more normal practice is probably to pre-transcode the video into a number of different bit rate formats and allow the client choose which one to request the next 'chunk' of the video from based on their current network conditions.

This approach is referred to as Adaptive Bit Rate streaming and uses streaming formats like HLS and MPEG-DASH.

Ultimately, it is a tradeoff between processing overhead and storage overhead:

  • the real time transcoding approach requires you to only store one copy of the video to serve to users, but it requires you to transcode the video each time a user wants to view it (unless the one transcoding you do store works for them).
  • the ABR approach requires you to store a copy of the video for each bit rate you want to serve, but you only have to do the transcoding once (for each bit rate).

It gets further complicated by the expected viewing profile of the videos - storage is a bigger issue if the video will only be watched once or twice a year, and processing a bigger issues if you will have 100,000 users a day viewing the same video.

As a note, the approach you describe is quite similar to a live ABR stream - the live stream will be transcoded in real time (or as close as is possible) to, for example, 5 different bit rate streams and the clients will request the video in, for example, 10 second chunks. The client decides which bit rate stream to take the next chunk from based on the network conditions.

The main difference from your proposal is that all bit rates are being produced all the time, not just the ones being requested by a client at that moment.

In practice, with a large enough client base and spread of network conditions the two approaches would actually be the same - i.e. if you have enough clients and enough different network conditions you will be creating a full range of low and high bandwidth streams, anyway.

Upvotes: 1

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