<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="IncrediMail 1.0" name=GENERATOR></HEAD>
<BODY style="BACKGROUND-POSITION: 0px 0px; FONT-SIZE: 12pt; MARGIN: 5px 10px 10px; FONT-FAMILY: Arial" bgColor=#ffffff background="" scroll=yes ORGYPOS="0">
<TABLE id=INCREDIMAINTABLE cellSpacing=0 cellPadding=2 width="100%" border=0>
<TBODY>
<TR>
<TD id=INCREDITEXTREGION style="FONT-SIZE: 12pt; CURSOR: auto; FONT-FAMILY: Arial" width="100%">
<DIV> </DIV>
<DIV> </DIV>
<DIV id=IncrediOriginalMessage><I>-------Original Message-------</I></DIV>
<DIV> </DIV>
<DIV id=receivestrings>
<DIV dir=ltr style="FONT-SIZE: 11pt" <i><B>From:</B></I> <A href="mailto:x264-devel@videolan.org">x264-devel@videolan.org</A></DIV>
<DIV dir=ltr style="FONT-SIZE: 11pt" <i><B>Date:</B></I> 01/17/07 06:17:25</DIV>
<DIV dir=ltr style="FONT-SIZE: 11pt" <i><B>To:</B></I> <A href="mailto:x264-devel@videolan.org">x264-devel@videolan.org</A></DIV>
<DIV dir=ltr style="FONT-SIZE: 11pt" <i><B>Subject:</B></I> [x264-devel] Re: Slices in x264</DIV></DIV>
<DIV> </DIV>
<DIV>On Tuesday 16 January 2007 22:57, Jeff Clagg wrote:</DIV>
<DIV>> I don't have much to add beyond that Mans is right.</DIV>
<DIV>></DIV>
<DIV>> From the most optimistic reckoning, using FEC at the transport stream</DIV>
<DIV>> layer adds 8.5% overhead to EVERY PID IN THE STREAM; compare that to</DIV>
<DIV>> using a few slices per frame, thus adding maybe 2% overhead in the</DIV>
<DIV>> video stream only - which may be enough to add a satisfactory amount of</DIV>
<DIV>> error resilience.</DIV>
<DIV> </DIV>
<DIV>This is true, but the extra error resilience is only satisfactory because in</DIV>
<DIV>digital TV streams there is an I picture every half a second which will fix</DIV>
<DIV>up any accumulating errors. And I'd be certain that this regular I picture</DIV>
<DIV>adds a lot more than 8.5% to the video bitrate. In other applications it</DIV>
<DIV>would be cheaper and more effective to add FEC to the stream.</DIV>
<DIV> </DIV>
<DIV>However, the original questioner was working in a packet based environment</DIV>
<DIV>and slices are useful there so that one lost packet does not mean one lost</DIV>
<DIV>picture. But error *concealment* would still need to be performed very soon</DIV>
<DIV>after despite this extra error *resilience*.</DIV>
<DIV> </DIV>
<DIV>Cheers,</DIV>
<DIV>-Ryan</DIV>
<DIV> </DIV>
<DIV>--</DIV>
<DIV>This is the x264-devel mailing-list</DIV>
<DIV>To unsubscribe, go to: <A href="http://developers.videolan.org/lists.html">http://developers.videolan.org/lists.html</A></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>--</DIV>
<DIV>No virus found in this incoming message.</DIV>
<DIV>Checked by AVG.</DIV>
<DIV>Version: 7.5.433 / Virus Database: 268.16.13/632 - Release Date: 01/16/2007 4:36 PM</DIV>
<DIV> </DIV>
<DIV>.</DIV></TD></TR>
<TR>
<TD id=INCREDIFOOTER width="100%">
<TABLE cellSpacing=0 cellPadding=0 width="100%">
<TBODY>
<TR>
<TD width="100%"></TD>
<TD id=INCREDISOUND vAlign=bottom align=middle></TD>
<TD id=INCREDIANIM vAlign=bottom align=middle></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><SPAN id=IncrediStamp><SPAN dir=ltr><A href="http://www.incredimail.com/index.asp?id=54475"><IMG alt="Add FUN to your email - CLICK HERE!" hspace=0 src="http://www2.incredimail.com/contents/stamps/imstp_emo_en.gif" align=baseline border=0></A></SPAN></SPAN></BODY></HTML>