I'm curious about the lookahead feature from Haswell. Is that a driver feature or it requires encoder integration for existing software? What encoder did Intel use in their comparison? It's not clear to me if I can use let's say MediaEspresso and lookahead is enabled or not.
Hi again Michael,
Regarding the quality discrepancy between QCP and LA you reported. Our encoder experts have explored this further and acknowledge that LA result in lower quality vs. CQP for this content, partially due to LA's obligation to maintain a local bitrate.
We do not have any immediate plans to address this specific scenario by changes to LA. But we will explore possible ways of improving future revisions of LA to handle this content and others better.
Recently I use sample_encode. exe has carried on the test of LookAhead, I downloaded the latest Intel SDK, and tested on the latest machinery, CPU: i7-4770, Os: Windows 7, Graphics Devices: HD 4600 Graphics, but I found that using the LookAhead get worse picture quality than without using LookAhead,the following is my command line arguments:
Use LookAhead:sample_encode.exe h264 -i C:\yuv.yuv -o C:\test_la.264 -w 720 -h 576 -hw -d3d -f 25 -b 1000 -u quality -la -lad 30
not use LookAhead:sample_encode.exe h264 -i C:\yuv.yuv -o C:\test.264 -w 720 -h 576 -hw -d3d -f 25 -b 1000 -u quality
the yuv.yuv is 720*576
Can you please share with us the graphics driver version you are using.
Also, if possible, please share your raw input YUV file since the quality looks the be dependent on content in your case,
First of all, thank you for your reply,my graphics driver is 22.214.171.124.3257, and the color of the YUV file is YUV420, width is 720 * 576, the original rate is 8000,I intercepted three images as the result of the experiment.And second ,i want to know that how to get better quality In the hardware encoding mode.
There is a more recent driver available from some sources that have known issues with LA, but the driver you are using is good for LA usages.
Your input content seems to be from a deinterlaced source with lots of jagged artifacts. It may be that the LA algorithm has some trouble with such content. Again, if you can please share the exact raw data (or part it) it would help us reproduce on our side.