于 2011-6-28 5:35, H. Peter Anvin 写道:
On 06/27/2011 12:33 AM, Wayne Xia wrote:
limitation: jpeg decoder have its limitation, it only accept jpg file with width=16*N, height=16*N. Strange thing is for some picture it have a good visual effect, while some with observable quality loss. bmp decoder only accept 24bpp file, with a resolution that a VESA mode could support. Recommended is 640x480(mostly used).
BMPs are notoriously bloated. Wouldn't it make sense to have a format with at least a modicum of compression? Odds are it would make a smaller image even with the extra code for the decompressor.
Yeah, BMP have a big size, but it would not lose quality of the image. So I'd like to make BMP decoder an option for seabios. If the user want to pass an image with compression, I think the old jpeg decoder was good enough. In my test, some jpeg picture have an observable quality lose after decoding, So I think in this situation user could pass a BMP file instead of jpeg file, it is a simple solution. I think this logo showing ability would be enabled only in following situation: The user want to show his brand picture to their customers, then he invoke the qemu with an option, then qemu tell seabios to show it. So in this case, I assume that the user did not require the virtual machine boot up as fast as it could, so the BMP file size would not be a problem. Anyway, in my test the time to transfer BMP file seems to be less than 1 second.