<div dir="ltr">OK this is apparently just a consequence of colorspace conversion--not a libva thing. Not sure if there is really a way to address it since going from BGR to NV12 data is gonna be lost because there are fewer bits.<div><br></div><div>Just running this pipeline in gstreamer 1.2.2 shows a lot of change in the image:</div><div><br></div><div>gst-launch-1.0 filesrc location=Howdy.png ! decodebin ! videoconvert ! video/x-raw,format=NV12 ! videoconvert ! imagefreeze ! ximagesink<br></div><div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 8, 2014 at 11:07 AM, Chris Healy <span dir="ltr"><<a href="mailto:cphealy@gmail.com" target="_blank">cphealy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I assume the black and white image is acceptable as it looks the same whereas the color one has some visual degradation, correct?<br><br>The i3 is Haswell based whereas the i5 is an older SandyBridge. I know
the Haswell is faster encode and decode wise, but I don't know about
quality. Is there a difference visually between the older i5 and newer i3 quality wise? <br><br></div><div>What are you using to do your color space conversion? I've been using one of the VPPs but was previously using libyuv on the CPU.<br></div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 8, 2014 at 9:02 AM, Matt Pekar <span dir="ltr"><<a href="mailto:mpekar@raineyelectronics.com" target="_blank">mpekar@raineyelectronics.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I've examined the behavior on Intel(R) Core(TM) i3-4130 and Intel(R) Core(TM) i5-2400. We target resolutions as low as 224x64 and up to 720P.<br><br>Another thing I'm noticing is that the colors used seem to matter. I put some white on black text up and it looks great. Maybe there is an issue with how I do my colorspace conversion from BGR to NV12...<br><br>I'm going to attempt to attach two pictures of what I'm seeing. They show the original .png image and what the encoder delivers side by side.<br></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 8, 2014 at 10:41 AM, Chris Healy <span dir="ltr"><<a href="mailto:cphealy@gmail.com" target="_blank">cphealy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hi Matt,<br><br></div>I've been using the libva with the Intel driver to encode and stream myself for quite some time now. There are a number of visual artifacts that I have encountered along the way, though the fuzziness you describe is not one of them. With the Intel driver, I would expect different visual behaviour depending on the particular HW you are using as each one is different. I'm using an i7-3517U to encode 1280x720 H.264 at 4Mbps. What are you working with?<br><br>Chris<br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Wed, Oct 8, 2014 at 7:18 AM, Matt Pekar <span dir="ltr"><<a href="mailto:mpekar@raineyelectronics.com" target="_blank">mpekar@raineyelectronics.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr">We use libva with the Intel driver to do live video streaming. In the encoding process we dynamically ramp the QP up and down as different content flows through.<div><br></div><div>There are cases where we display simple text messages for many seconds. In these cases I'd like to send my QP down to 1--highest quality--and get as close to a lossless encode as possible.</div><div><br></div><div>What I'm seeing is that on fonts and sharp lines a little bit of encoding will be done regardless, leaving the text slightly fuzzy. I tried the new VAEncMiscParameterTypeQualityLevel setting, but it only had two levels (1 and 2) and they didn't seem to affect the picture at all.</div><div><br></div><div>Are there any settings I might try to ramp the quality up even further? Is the fuzziness I'm seeing in the text inherent to the h264 standard, or is this just what Intel's implementation happens to do?<br></div><div><br></div></div>
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