webp support deocde to etc, pvrtc texture format

[gnet...@gmail.com]

Can webd support decode to mobile friendly texture format, such as etc, pvrtc, i know it will cost much more time to decode to these format, i just want to know does it possible, or does webp develop team has any plan to support it?

[Pascal Massimino]

Hi,

On Fri, Nov 10, 2017 at 3:05 AM, <gnet...@gmail.com> wrote:

Can webd support decode to mobile friendly texture format, such as etc, pvrtc, i know it will cost much more time to decode to these format, i just want to know does it possible, or does webp develop team has any plan to support it?

there's been some discussions about going directly from webp to pvrtc (or ASTC, or ETCn, or ...), but there's some difficulties:

   a) both ends are quite different formats (colorspace difference, fixed bitrate vs variable bitrate, block sizes, etc.). It's hard to find overlapped processing to speed upon.

   b) developers often store their textures directly in PVRTC/ASTC/... format because decoding speed is what matters most compared to compression efficiency (which is lower priority). The typical use case is when a player changes level in a game and you need to reload all the textures on GPU as fast as possible.

Agreed, b) can be mitigated at install time by downloading the assets in WebP format and recompressing  them in PVRTC (despite a longer install time, which can upset users).

But one needs a fast and efficient PVRTC encoder.

Still, a) is problematic and there's not much more to gain over using the regular tool chain: webp->raw ARGB->pvrtc (e.g.)

hope it helps,

skal/

[gnet...@gmail.com]

thanks for your reply, we are now decode webp to argb in our game in runtime, i just think maybe we can decode to pvrtc( or etc..) when we have enough free time for decoding. do you know how much time will cost to decode to pvrtc (or etc) compare to decode to argb?

在 2017年11月10日星期五 UTC+8下午6:39:48，skal写道：