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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hi Sebastian,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">We don’t currently support the ability to adjust the quantization in specific areas of the picture. If you share samples of what you’re seeing it would help us understand the challenge better.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Best regards,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Tom</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> x265-devel [mailto:<a href="mailto:x265-devel-bounces@videolan.org">x265-devel-bounces@videolan.org</a>] <b>On Behalf Of </b>Sebastian Sylwan<br><b>Sent:</b> Monday, January 19, 2015 11:27 AM<br><b>To:</b> x265-devel<br><b>Subject:</b> [x265] Fwd: Encoding question</span></p><p class="MsoNormal"> </p><div><div><div><p class="MsoNormal">Hi, </p><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">This is my first message to the list, so please forgive me if it is not fully appropriate for it. </p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">I am experimenting with encoding video whose final application is to be merged with static images around it. I have reached an appropriate level of compression, but I am seeing some quantization issues at the edge of the frames, that would probably be perceptually ok, if they weren't adjacent to a static image that is supposedly blended to the video. This is really only noticeable in the darker areas of the image, and in regions that are static, and the artifact is mostly noticeable since there is a tinting towards green (and a slight brightening). </p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">I was wondering if there is a way to tell the encoder to quantize less aggressively around the edges (or in any specific area). Alternatively, also biasing the quantization towards the darker regions of the image may work. Since the artifacts seem to build overtime, I wonder if there is a drifting of a DC component also happening.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">Any suggestion appreciated. Of course I could increase the bitrate, but the rest of the image is ok.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">Thank you. </p></div><div><p class="MsoNormal"><span style="color:#888888"> </span></p></div><div><p class="MsoNormal"><span style="color:#888888">S </span></p></div></div></div><p class="MsoNormal"> </p></div></div></body></html>