advice on live capture to disk

[Chuck Crisler]

How many threads is the encoder using? 6-7 years ago when I was working on
a software only video conferencing system, we set up a 4 core (real cores,
not hyperthreaded) Zeon 3 GHz system capturing 1080p. We could participate
in conferences with the hardware/embedded systems and no one could tell the
difference. That was 1080p encode and decode and the CODEC was single
threaded. Yes, h264 should be able to handle it, especially since you only
need to capture/encode and save.

On Tue, Sep 30, 2014 at 3:13 AM, Edward Hervey <bilboed at bilboed.com> wrote:

> Hi,
>
>
> On Tue, 2014-09-30 at 01:27 -0400, John Bazik wrote:
> > I’ve been trying to construct a pipeline to reliably capture a 720p
> > camera feed (w/ pcm audio) for 1 to 2 hours and save it to disk.  It
> > needs to be sufficiently high quality for me to transcode it later into
> > lower resolutions and bitrates for streaming on demand.  I’m capturing
> > from a blackmagic intensity pro, on a reasonably powerful 6-core
> > machine.  I knock it down from 60fps to 30fps, but I’m otherwise trying
> > to preserve the quality and resolution.
> >
> > I’ve tried a variety of codecs (theora, x264, mjpeg, huffyuv) and I
> > find myself stymied.  I’m not so concerned about compression, though at
> > 200GB/hr, raw video is a bit unwieldy.  I spent hours tinkering with
> > x264, but could not eliminate weird wavy artifacts.  I could not get
> > high quality from theora without dropping frames.  I couldn’t get mjpeg
> > to work (openmjpegenc).  I thought I had it with huffyuv (even at
> > 96GB/hr), but it, too, dropped frames after a while, though it was
> > running at about 25% cpu.  I don’t need a perfect copy, perfect-looking
> > is good enough.
> >
> > It feel like this should work.  Can anyone point me in the right
> > direction?  Am I better off with something like x264, or with huffyuv?
> > When I’m using lossless compression, could I be dropping frames due to
> > i/o bandwidth limitations to a standard 7200rpm sata hard disk?
>
>   Raw video on that ... is definitely not going to be possible :) But
> the other compressed formats you mention should be fine i/o-wise.
>
>   What version of GStreamer are you using ? What does your pipeline look
> like ? Do you get any warnings (GST_DEBUG=2) ? What are those "weavy
> artifacts" you mention ?
>
>    Edward
>
> >
> > John
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>
>
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