Re: some little your help about WebM project Quicktime Component if you don't mind it.

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Ryan Thompson

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Jul 30, 2012, 9:53:39 AM7/30/12
to Hyoung joon Jun, webm-d...@webmproject.org
+webm-discuss

Sorry for the late reply Hyoung,  I've been away from my email for the last week.

Yes, there is a limit on cluster sizes in webm.  It is a subset of matroska (you can google the spec if you want).

The quicktime component should automatically generate a new cluster when needed (without any intervention on your part).  If it isn't that is a bug in the component.  To be honest I haven't tested the QT component a lot with live streaming.  A couple things to consider:
- You will want set the vp8 settings to live encoding to make sure that the encoder can keep up.  (they aren't by default)
- You might want to make sure the QT encoder is your best tool.  If you are using windows consider directshow.

Hope that helps point you the right direction.


On Mon, Jul 23, 2012 at 3:02 AM, Hyoung joon Jun <hi.j...@gmail.com> wrote:
Hello. Ryan Thompson

I am wondering if I can get quick your help/comment about "WebM project Quicktime Component".
currently, I am developing application code of Webm live streaming on windows platform using QT library/OpenCV(webcam capture) with stream-m server. however, my streaming is only for 33 seconds.  I checked the webm muxing guideline. There is a description about 32.xx seconds limitation for a cluster. 

so,  I am trying to generate new cluster in vp8 encoding loop if the video blocks reaches to total 10~ 15 seconds to develop working prototype. but it does not work well. I don't have apple platform and I have no way to test "WebM project Quicktime Component"

I am trying to narrow down to find possible root cause this happening.  If you just pinpoint possible cause or I miss some, I can look into my code. I guess I am missing some principle of live webm muxing.

Thank you for reading this email.
regards
joon


Matthew Heaney

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Jul 30, 2012, 2:10:53 PM7/30/12
to webm-d...@webmproject.org, Hyoung joon Jun
You mentioned that you're on Windows - have you tried using DirectShow?
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Hyoungjoon Jun

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Aug 2, 2012, 8:40:16 PM8/2/12
to webm-d...@webmproject.org, Matthew Heaney
I have not tried to use directshow. I just take a look about its source
code. I have satisfy some requirements. such as windows platform, must
use QT, must get real-time video/audio capture. must stream out to html5
capable web browsers and so on.

Later, i also have to work on vorbis sound/ webm muxing in realtime. do
you think if the directshow can accept those my requirements as
API/runtime library/CLI ?
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