Posted: Thu 8 Mar 2007, 1:29 Post subject: another question about pixel ratio converting
as we know, computers display video/graphic in square pixels. but many video sources are in rectangle pixels.
if an application, such a s a player, recognizes a video's pixel ratio correctly, if needed, does it do the job of converting to square pixels, or just pass the origional pixel ratio info to the video card's driver, let the video card do the converting job?
as for nle softwares, the situation is different. since the video clips used maybe have different pixel ratios. well, say, there's a pal widescreen project with pixel ratio=1.422. but the clips and graphics imported have such pixels, such as 1.422, 1.0, 1.067, 1.33, 1.5. then will the nle software convert all the clips to 1.422 ratio (in fact there may be one more job of vertical lines converting ), and pass the info to video card driver, or just convert everything to 1.0 square ratio?
Joined: 04 Feb 2003 Posts: 587 Location: Lisboa, Portugal
Posted: Sat 10 Mar 2007, 0:00 Post subject: Re: another question about pixel ratio converting
compusic wrote:
if an application, such a s a player, recognizes a video's pixel ratio correctly, if needed, does it do the job of converting to square pixels, or just pass the origional pixel ratio info to the video card's driver, let the video card do the converting job?
That depends on the API used to display the video. Some APIs support hardware-accelerated resizing (in which case the program simply send the original pixel data plus the output size, and lets the driver do the scaling), other do not (wich means the player needs to do all resizing internally).
Quote:
as for nle softwares, the situation is different. since the video clips used maybe have different pixel ratios. well, say, there's a pal widescreen project with pixel ratio=1.422. but the clips and graphics imported have such pixels, such as 1.422, 1.0, 1.067, 1.33, 1.5. then will the nle software convert all the clips to 1.422 ratio (in fact there may be one more job of vertical lines converting ), and pass the info to video card driver, or just convert everything to 1.0 square ratio?
In NLE software, the graphics driver is more or less irrelevant, since it's only used for the preview window. The software must handle all the calculations internally (some NLE software uses the GPU to accelerate a few effects, but the main processing is still all done on the main CPUs, and isn't influenced by the graphics driver).
Most editing software lets you pick between different ways to handle source video (ex., resize to full screen, keep original size, maintain aspect ratio or assume 1:1, etc.).
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