[Icecast] Webm files written without duration in header

Fred Gleason fredg at paravelsystems.com
Wed May 1 20:30:57 UTC 2019

On Wed, 2019-05-01 at 22:06 +0200, Sytze Visser wrote:
> The point is that if I can successfully stream mp4 with H.264 and AAC
> encoding without any issues to icecast, I can then use ffmpeg to
> turn it into HLS which then solves my iOS support issue. The CPU
> cost of repackaging MP4 into HLS architecture should be minimal
> because at the core it’s all H.264. No transcoding! Low CPU objective
> achieved!

So all FFMPEG is doing is segmenting the stream and generating the m3u8
index? Yes, I'd expect that to be quite efficient.

> My question remains
> If webm/ogv is supported but mp4 not, what are the technical
> differences
> in how icecast handles the one and not the other? What does icecast
> manage/do for supported formats as opposed to unsupported ones?

It's been a few years since I looked at the source, but IIRC adding
support for a new codec is pretty simple -- mostly a matter of getting
it to recognize and emit the correct mimetype(s).

Of course, you'll also need an ICES client that is capable of
supporting the desired codec. That may be more challenging than hacking
Icecast itself.


| Frederick F. Gleason, Jr. |             Chief Developer             |
|                           |             Paravel Systems             |
|  There is only one thing worse than having your competitors trying  |
|  to inter-operate with your systems - and that is to have your      |
|  competitors *not* trying to inter-operate with your systems.       |
|                                                                     |
|                                          -- Alan(UK), GrokLaw.net   |

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