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<DIV id=IncrediOriginalMessage><I>-------Original Message-------</I></DIV>
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<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 06:11:56</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>Guillaume Poirier wrote:</DIV>
<DIV>> Måns Rullgård wrote:</DIV>
<DIV>>> Guillaume Poirier <<A href="mailto:gpoirier@mplayerhq.hu">gpoirier@mplayerhq.hu</A>> writes:</DIV>
<DIV>>> Using error correcting coding at the transmission layer substantially</DIV>
<DIV>>> increases the bitrate. With slices a transmission error will ruin the</DIV>
<DIV>>> rest of the slice, while other slices still decode properly.</DIV>
<DIV>>> Sometimes a little damage here and there is acceptable if it means you</DIV>
<DIV>>> can keep the bitrate down. Besides, you don't always have control</DIV>
<DIV>>> over the transmission encoding.</DIV>
<DIV>>></DIV>
<DIV>>> Put another way, slices limit the scope of the damage caused by</DIV>
<DIV>>> whatever transmission errors make it through your error correction</DIV>
<DIV>>> layers.</DIV>
<DIV>>></DIV>
<DIV>>> Anyone who has watched digital TV should appreciate the usefulness of</DIV>
<DIV>>> slices.</DIV>
<DIV>></DIV>
<DIV>> Mmmm. I guess I did not understand what "error concealment" meant. My</DIV>
<DIV>> dictionary translates it to "dissimulation des erreurs" which more or</DIV>
<DIV>> less translates back in English as "error hiding", which by my book</DIV>
<DIV>> means that if an error occurs, it doesn't show, up to a certain amount</DIV>
<DIV>> of errors you can't recover.</DIV>
<DIV>></DIV>
<DIV>> As far as I understand, slices don't allow that, that's why I thought</DIV>
<DIV>> that better error correction blocks was the solution.</DIV>
<DIV>></DIV>
<DIV>> But now that I understand what "error concealment" means, and I see</DIV>
<DIV>> that slices seem like the right tool for that job.</DIV>
<DIV>></DIV>
<DIV>> Sorry for the trouble. I'm learning smth new every day :-)</DIV>
<DIV> </DIV>
<DIV>What slices support as-is is spatial "error containment". Together with</DIV>
<DIV>a defined I frame interval (or at least intra-mb interval) temporal</DIV>
<DIV>"error containment" is provided as well.</DIV>
<DIV> </DIV>
<DIV>If I get it right, the new method tries to "fix" parts of the broken</DIV>
<DIV>stream based on surrounding motion vectors. That could be called "error</DIV>
<DIV>concealment" but has nothing to do with slices.</DIV>
<DIV> </DIV>
<DIV>A better tool instead of slices is that completely coded macroblock</DIV>
<DIV>which resets the stream. It can be placed as often as needed depending</DIV>
<DIV>on current line quality (if there is a feedback on that).</DIV>
<DIV> </DIV>
<DIV>bis besser,</DIV>
<DIV>T0B1A5</DIV>
<DIV> </DIV>
<DIV>--</DIV>
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