<div>The reason for the increace in PSNR is the P.</div><div>Think of what the P stands for.</div><div><br></div><div>Your ASNR would be the same or lower, however.</div><div>Try doing this with the increace to 14 and collecting the ASNR and PSNR going downwards and plot a graph.</div>
<div>You'll see what I mean :)</div><div><br></div><div>Peak Signal to Noise Ratio</div><div>Average Signal to Noise Ratio</div><div>The latter is more important for compression and the former is more important for finding how to fix the ladder (when what is going on when it reaches peak)</div>
<div><br></div><div>Logs please?<br><br><div class="gmail_quote">On Tue, Jun 29, 2010 at 5:25 PM, john sisi <span dir="ltr"><<a href="mailto:sisi.john1@gmail.com">sisi.john1@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Dear All,<br>
<br>
I performed an experiment using x264 to find the effect of using<br>
different reference frames on the PSNR performance. I got a somehow<br>
weird result: it seems that the PSNR goes up (by about 0.2dB on<br>
Foreman CIF @256kbps) as the distance to the reference frame is<br>
increased (from 3 to 15).<br>
<br>
I set the number of reference frame to 15 using "--ref 15" and I<br>
changed the code such that I was able to select only one of these 15<br>
reference frames for encoding the frames. For example, in<br>
"x264_mb_analyse_inter_p16x16" I set "i_ref" to 5 just before<br>
"REF_COST( 0, i_ref )" to use only the 6th reference frame. I applied<br>
the same change on the other relevant functions like<br>
"x264_mb_analyse_inter_p16x8".<br>
<br>
My expectection is that the PSNR values must go down as we use farther<br>
reference frames but is this result reasonable? Thanks,<br>
John<br>
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</blockquote></div><br></div>