[Icecast] Webm files written without duration in header

Thomas B. Rücker thomas at ruecker.fi
Fri May 3 07:19:40 UTC 2019


On 5/1/19 5:56 PM, Sytze Visser wrote:
> Thanks Thomas. I was hoping to avoid remuxing as my objective is to
> run an extremely lightweight server. Just tested and the CPU runs
> between 9% and 23% for a lecture of 90 minutes - took 18sec. Yes it's
> a lightweight server, but like I said, that's the objective, and quite
> a nice challenge :-) CPU = cost and if you have to remux for 1000
> clients in a day, integrity of live streams currently running are at
> risk. Going to put some more thinking into it.

There should be no need to remux each file more than once, so unless you
produce 1000 files per day, I dont't understand your point.
Even in that case all those files won't be created at the exact same
point in time and even if it is really easy to devise a funnel/queue
that does the remuxing at low priority.

Please note again that remuxing is NOT reencoding, the encoded
information is not touched and it's very quick and efficient because of

> *You mentioned:*
> "Does this mean you are using the dump feature to write the complete
> stream to a file on the machine running Icecast?"
> */Yes/*. Curious as to why you ask. Can one perhaps point it to a
> named pipe and pass to ffmpeg to remux and be a little more efficient
> on CPU? Alternatively, can you do <dump-file>ffmpeg -c copy
> .....</dump-file> ? Is it supported? Have been on Linux for less than
> a year so not sure if at all possible? I have no idea yet what a 1000
> fifo's will do.

Just needed to make sure how the files are generated. There may be
slight differences between dumping a stream via e.g. curl or wget vs
using the dump file. Nothing that matters to your use case though as
before presenting any of these you should very much remux them to ensure
file integrity as static files.

Also *please* avoid sending HTML emails to the mailing list. Thanks.



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