Re: Saved live stream problem

Walter Tak wrote:

Red5 just pushes data to your client.

You want your client to buffer a few seconds of video at least. So
bufferLength should be somewhere between 2 to 10 seconds, depending on the
quality of your link/bandwidth. If you have a clear line and can download at
speeds of 10 mbit/sec without problems then any stream of less than 5
mbit/sec should be viewable without any hickup.

However hickups do occur now and then between the server and your client(s)
and that's why you want a little buffer. For teleconfering with live-to-live
streams you might want to have a low buffer to avoid the 'latency', for
viewing movies/longer videos you could go for 5-10 seconds buffer for near
perfect viewing.

For those that care ; there are various ways to do 'dynamic stream
switching' by trying to determine the actual bandwidth of a client on the
client-side with some action-script code. Various code-snippets can be found
here:

http://labs.influxis.com/?p=269

http://www.adobe.com/devnet/flashmediaserver/articles/dynstream_on_demand.html

http://www.adobe.com/devnet/flashmediaserver/articles/fms_dual_buffering.html

The last link is very interesting ; Fabio did back in the days some nice
investigation ; the graph shows real-life behaviour of your 'consumer-grade'
internet-connection ; the available bandwidth is far from 'stable'. Besides
that your own client could suddenly have limited resources (virusscanner
starts, you start another download in the background, your torrent decides
to upload at 95% of your capacity, the server might hit a spike due to 15
other requests , the creation of statistics at exactly 00:00 hours or a
backup operation.

Once you understand that streaming is balancing on a cord above the grand
canyon you'll see that there are no default values that will work in all
situations. You want to have some dynamic logic. The easiest thing is to do
that on client side.

The concept is simple ; check the bandwidth by sending small packets of
random-data. Measure how long it takes to transfer those little packets to
the server. Calculate the supposed available bandwidth. Switch to a stream
with a matching bitrate. This assumes you store your video in at least two
or more bitrates. Think of 100 kbit , 500 kbit, 1000 kbit etc. Like the
Youtube "HD" option.

----- Original Message -----
From: "edjayks" <edjayks@yahoo.com>
To: <Red5@osflash.org>
Sent: Tuesday, 14 July 2009 02:35
Subject: Re: [Red5] Saved live stream problem


>
> The buffer length at the client site is left at 0.1 seconds, this setting
> was
> fine when i run it with Red5 0.8 RC1. Does the red5 have a setting for
> buffer length too? If yes, where do i find it?
>
> The file itself is around 2.5Megabytes for 2minutes of recording.
>
> Well, if the file itself is corrupt, don't you think it's the Red5 that is
> causing it?
>
>
> Andy Shaules wrote:
>>
>> sounds like the buffer length is too little.
>>
>> and the file is too phat.
>>
>> Or the file itself is corrupt.
>>
>> ----- Original Message -----
>> From: "edjayks" <edjayks@yahoo.com>
>> To: <Red5@osflash.org>
>> Sent: Monday, July 13, 2009 1:32 AM
>> Subject: Re: [Red5] Saved live stream problem
>>
>>
>>>
>>> Ok, i did one more testing, I put the recorded .flv file into Flash
>>> media
>>> server vod's directory, then i use the client application built in Adobe
>>> flex, the video plays smoother, it plays smooth for about 3-6 seconds
>>> then
>>> it pause for 1-2 seconds then it plays again, and the play and pause
>>> thing
>>> repeat until the video has finished playing.
>>> Compared to it being stream from red5, the video would be jerky every
>>> second, like pause and play for a few times in every seconds until the
>>> end
>>> of the video.
>>>
>>> Somebody, please help.:-(
>>>
>>>
>>> edjayks wrote:
>>>>
>>>> I have a client that broadcast video and audio, then on the server, it
>>>> would save the stream into a flv file.
>>>> When i playback the video, it's very jerky.
>>>> I'm using Red5 hudson build #156. It was fine before the patch from
>>>> absolute to relative timestamp.
>>>>
>>>> More information, on the server code, I call
>>>>
>>>> ClientBroadcastStream stream = ...;
>>>> stream.saveAs(steamNAme,false);
>>>>
>>>> to start recording the live stream. Then i call
>>>>
>>>> ClientBroadcastStream stream = ...;
>>>> stream.stopRecording();
>>>>
>>>> to stop recording the live stream.
>>>>
>>>> I tried creating a simple video playback application in openlaszlo and
>>>> adobe flex, both will play the video jerkyly. Seems like the video
>>>> pause
>>>> and play very frequently.
>>>>
>>>
>>> --
>>> View this message in context:
>>> http://www.nabble.com/Saved-live-stream-problem-tp24403684p24457882.html
>>> Sent from the Red5 - English mailing list archive at Nabble.com.
>>>
>>>
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>>> Red5 mailing list
>>> Red5@osflash.org
>>> http://osflash.org/mailman/listinfo/red5_osflash.org
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>>
>>
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>
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> Sent from the Red5 - English mailing list archive at Nabble.com.
>
>
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