Hi, <br><br>Thanks for your kind information.&nbsp; Yes, recently I digged the spice implementation and found some clues like what you mentioned :-)&nbsp; I still have some questions regarding stream data:<br>1) from version 0.63 source code, it seems that 32bit bitmap format is not supported to use MJPEG, why? <br>2) for 32bit bitmap(format 9), there are two methods to process it depending on JPEG compression flag.&nbsp; If bandwidth is ok, it will use high quality delivery. Otherwise it will use some lossy-compression algorithm. So what's the difference between the lossy-compression and MJPEG?<br>3) I'm really puzzled by the spice marshaller code... it seems that they are generated by some python modules/scripts, could anyone share something about it and the purpose?<br><br>Have a nice day!<br><br>Thanks,<br>Liang<div></div><br><pre><br>At&nbsp;2011-01-10&nbsp;18:16:30£¬"Alon&nbsp;Levy"&nbsp;&lt;alevy@redhat.com&gt;&nbsp;wrote:

&gt;On&nbsp;Fri,&nbsp;Dec&nbsp;17,&nbsp;2010&nbsp;at&nbsp;09:51:39PM&nbsp;+0800,&nbsp;ÁºÁÁ&nbsp;wrote:
&gt;&gt;&nbsp;Dear&nbsp;all,
&gt;&gt;&nbsp;
&gt;&gt;&nbsp;Several&nbsp;days&nbsp;ago&nbsp;I&nbsp;tried&nbsp;using&nbsp;spice&nbsp;and&nbsp;really&nbsp;impressed&nbsp;by&nbsp;its&nbsp;&nbsp;performance,&nbsp;really&nbsp;good&nbsp;job!&nbsp;Then&nbsp;I&nbsp;tried&nbsp;to&nbsp;dig&nbsp;the&nbsp;details,&nbsp;mainly&nbsp;focus&nbsp;on&nbsp;graphics&nbsp;subsystem&nbsp;and&nbsp;learned&nbsp;a&nbsp;lot.&nbsp;Thank&nbsp;you!
&gt;&gt;&nbsp;
&gt;&gt;&nbsp;During&nbsp;studying&nbsp;the&nbsp;handling&nbsp;for&nbsp;stream&nbsp;data,&nbsp;I'm&nbsp;lost&nbsp;in&nbsp;the&nbsp;interaction&nbsp;of&nbsp;qemu&nbsp;display&nbsp;driver&nbsp;and&nbsp;spice&nbsp;server.&nbsp;So&nbsp;I&nbsp;send&nbsp;this&nbsp;mail&nbsp;to&nbsp;consult&nbsp;you&nbsp;experts&nbsp;some&nbsp;simple&nbsp;questions&nbsp;&nbsp;:-)
&gt;&gt;&nbsp;1.&nbsp;For&nbsp;the&nbsp;video&nbsp;played&nbsp;in&nbsp;Guest&nbsp;OS,&nbsp;my&nbsp;understanding&nbsp;is&nbsp;that&nbsp;media&nbsp;player&nbsp;(for&nbsp;example,&nbsp;mplayer)&nbsp;in&nbsp;Guest&nbsp;OS&nbsp;will&nbsp;decode&nbsp;the&nbsp;video&nbsp;file&nbsp;and&nbsp;the&nbsp;display&nbsp;driver(qxl&nbsp;driver)&nbsp;will&nbsp;process&nbsp;decoded&nbsp;frames.&nbsp;Is&nbsp;it&nbsp;true?&nbsp;Then&nbsp;display&nbsp;driver&nbsp;will&nbsp;store&nbsp;frame&nbsp;data&nbsp;into&nbsp;stream&nbsp;chain&nbsp;of&nbsp;RedWorker?&nbsp;Each&nbsp;frame&nbsp;will&nbsp;be&nbsp;stored&nbsp;or&nbsp;just&nbsp;some&nbsp;key&nbsp;frames?&nbsp;For&nbsp;above&nbsp;descriptions,&nbsp;they&nbsp;are&nbsp;just&nbsp;my&nbsp;assumption,&nbsp;I&nbsp;have&nbsp;not&nbsp;found&nbsp;provens&nbsp;from&nbsp;the&nbsp;code.&nbsp;Help&nbsp;you&nbsp;could&nbsp;share&nbsp;some&nbsp;hints&nbsp;about&nbsp;the&nbsp;detail.
&gt;
&gt;The&nbsp;frames&nbsp;are&nbsp;fed&nbsp;one&nbsp;by&nbsp;one&nbsp;to&nbsp;the&nbsp;mjpeg&nbsp;encoder&nbsp;on&nbsp;the&nbsp;server,&nbsp;and&nbsp;its&nbsp;output&nbsp;is&nbsp;sent&nbsp;to&nbsp;the&nbsp;client&nbsp;if&nbsp;one&nbsp;is&nbsp;connected.&nbsp;Look&nbsp;in&nbsp;red_worker.c,&nbsp;track&nbsp;mjpeg_encoder&nbsp;and&nbsp;streams&nbsp;(streams&nbsp;belongs&nbsp;to&nbsp;RedWorker).
&gt;
&gt;&gt;&nbsp;2.&nbsp;Each&nbsp;stream&nbsp;data&nbsp;will&nbsp;be&nbsp;encoded&nbsp;using&nbsp;MJpeg&nbsp;on&nbsp;server&nbsp;side&nbsp;and&nbsp;decoded&nbsp;on&nbsp;client&nbsp;side.&nbsp;Have&nbsp;the&nbsp;team&nbsp;considered&nbsp;higher&nbsp;compression&nbsp;rate&nbsp;codec,&nbsp;like&nbsp;mpeg-4?&nbsp;&nbsp;If&nbsp;yes,&nbsp;could&nbsp;you&nbsp;help&nbsp;share&nbsp;the&nbsp;reason&nbsp;why&nbsp;it's&nbsp;not&nbsp;adopted?&nbsp;My&nbsp;understanding&nbsp;is&nbsp;that&nbsp;video&nbsp;application&nbsp;is&nbsp;the&nbsp;killer&nbsp;application&nbsp;and&nbsp;consume&nbsp;much&nbsp;bandwidth&nbsp;for&nbsp;remote&nbsp;display&nbsp;system.
&gt;
&gt;We&nbsp;should&nbsp;definitely&nbsp;try&nbsp;adjusting&nbsp;the&nbsp;codec&nbsp;and&nbsp;it's&nbsp;parameters&nbsp;based&nbsp;on&nbsp;bandwidth/latency&nbsp;and&nbsp;cpu&nbsp;requirements.
&gt;
&gt;&gt;&nbsp;
&gt;&gt;&nbsp;Thank&nbsp;you&nbsp;and&nbsp;have&nbsp;a&nbsp;nice&nbsp;weekend!
&gt;&gt;&nbsp;
&gt;&gt;&nbsp;Thanks,
&gt;&gt;&nbsp;Liang
&gt;
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&gt;
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