<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><blockquote type="cite">In any case, there's an existence proof countering this argument: YouTube, Hulu, Netflix... They're all VBR.<br></blockquote><div><br></div>They're also all TCP. But we stream via UDP. Apples and oranges. (Things are a lot easier if you're using a request-response protocol (like TCP), and therefore don't mind waiting arbitrarily long for data to get delivered.)</div><div><br></div><div>Anyway, what I didn't make sufficiently clear in my January 2011 email was that when I ran my experiment, altering our server code (along with the index file format) to stream TS files using precise (rather than predicted) inter-Transport-Packet durations, it HAD NO EFFECT on the way that VLC (as the RTSP media player client) displayed a VBR TS stream. I.e., VLC played the stream in the same 'jittery' fashion as before. It wasn't any better. It might have even been a bit worse.</div><div><br></div><div>It therefore became clear to me that I had been wrong about the 'accurate inter-packet duration calculation' issue being the cause of the problem. That turned out to be a 'red herring'. The real problem was the bursty nature of the VBR stream itself.</div><div><br></div><div>If you want to transmit a highly VBR stream using a datagram protocol (like RTP), then you need to make sure that your client has a lot of buffering, and with a high 'low water mark' (much higher than the 100ms (I think) default that VLC uses).</div><br><br><div apple-content-edited="true">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">Ross Finlayson<br>Live Networks, Inc.<br><a href="http://www.live555.com/">http://www.live555.com/</a></span></span>
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