- From: Philip Jägenstedt <philipj@opera.com>
- Date: Mon, 14 Sep 2009 09:47:37 +0200
- To: "Ian Hickson" <ian@hixie.ch>
- Cc: "Simon Pieters" <simonp@opera.com>, "public-html@w3.org" <public-html@w3.org>
On Mon, 14 Sep 2009 08:48:59 +0200, Ian Hickson <ian@hixie.ch> wrote: > On Thu, 3 Sep 2009, Philip Jägenstedt wrote: >> On Thu, 03 Sep 2009 13:47:41 +0200, Ian Hickson <ian@hixie.ch> wrote: >> > On Mon, 31 Aug 2009, Simon Pieters wrote: >> > > >> > > The following paragraph: >> > > >> > > "The intrinsic width and intrinsic height of the media resource are >> > > the dimensions of the resource in CSS pixels after taking into >> > > account the resource's dimensions, aspect ratio, clean aperture, >> > > resolution, and so forth, as defined for the format used by the >> > > resource." >> > > >> > > ...doesn't say whether to scale up or down when taking into account >> > > aspect ratio. >> > >> > Wouldn't that be up to the video format? >> >> No, video formats only give the size in pixels and the pixel aspect >> ratio (or alternatively frame aspect ratio). The only constraint is that >> the aspect ratio be correct, which forces us to choose how to achieve >> that. Assuming one dimension remains unchanged: >> >> 1. always scale up >> 2. always scale down >> 3. always scale x-dimension >> 4. always scale y-dimension >> >> We're suggesting #1. From the rest I've only seen #3 used in actual >> media players. > > Fair enough. I've specced #3 (#3 and #4 are simpler to implement than #1 > or #2, and the extra complexity doesn't seem to gain us much. I've never > heard of anamorphic video data with a ratio less than 1.0, so assuming my > experiences are representative, it's the same as #1 in most cases > anyway). Actually, standard 720x480 4:3 NTSC DVD video has an pixel aspect ratio of 8:9 and there is no shortage of it. While #3 is easier to both spec and implement, both we and Mozilla have already independently chosen to implement (and write tests for) #1, so I'd much prefer if that were specced. Chrome seems to not do anything and I don't know how to produce a suitable test file for Safari. -- Philip Jägenstedt Core Developer Opera Software
Received on Monday, 14 September 2009 07:48:17 UTC