<br><br><div class="gmail_quote">On Wed, Sep 1, 2010 at 4:14 AM, Diego Torres <span dir="ltr"><<a href="mailto:torres.diego@ttcpl.com.au">torres.diego@ttcpl.com.au</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div style="word-wrap:break-word"><div>Thanks mate, that was it... sort of.</div><div><br></div><div>I added '-threads 0' and that made all four cores to be utilized.</div><div>At first I realized that there is a "multiple threading" checkbox on myth export and used</div>
<div>that . But it adds '-threads 2' to the command so it only uses two cores.</div><div><br></div><div>With '-threads 0' on both passes it only took 1.5 hours for the first pass and 1 hour to for the second pass.</div>
<div>Still not as fast as Airvideo but a heck of a lot faster than before.</div><div><br></div><div>The only things I noticed are:</div><div>- The 1 GB RAM was being used with the SWAP going to 200MB or so. I upped the memory to 2GB and it still used it all but did not use swap.</div>
<div>- Even though all 4 cores are being used, none are used more than 80% and there is always one that </div><div>oscillates between 30 and 80%. With Airvideo all 4 cores are pretty much pegged at 80% the whole time.</div>
<div>- I am guessing that the CPU does not go to 100% because of I/O bottlenecks. It could be that the 500GB IDE HDD /controller combo</div><div>just can't keep up with ffmpeg using all four cores.</div><div>- The output file is twice as big as Airvideo's so there is definetely a mismatch on the settings. I need to investigate that.</div>
<div>- I realized that myth export uses a two pass approach whilst Airvideo uses a one pass approach</div><div>(because the output file starts to fill up immediately). Doing some reading on the ffmpeg lit it says that a two pass</div>
<div>approach is required with a Variable Bit Rate and in general is recommended for quality output.</div><div>I reckon the quality from airvideo's one pass is more than good for the ipad so I will try hacking the script (time permittiing) to do a one pass only</div>
<div>and compare the conversion time.</div><div><br></div><div><br></div></div>
<br></blockquote></div><br><div>The file size difference is likely the version of ffmpeg and x264 that you are using. I looked at airvideo earlier in the year and found the difference in file size as well. When I followed Fakeoutdoorsmen's tutorial on building your own ffmpeg, the file sizes shrank to the same size as airvideo. </div>
<div><br></div><div><a href="http://ubuntuforums.org/showthread.php?t=786095">http://ubuntuforums.org/showthread.php?t=786095</a></div><div><br></div><div>These are the ffmpeg settings I am using:</div><div><div>ffmpegArgs=" -acodec libfaac -ab 128k -s 320x240 -vcodec libx264 -vpre slow -vpre ipod320 -threads 0 -f ipod"</div>
</div><div><br></div><div>Good luck.</div><div>Chris.</div>