- From: Pierre-Anthony Lemieux via GitHub <sysbot+gh@w3.org>
- Date: Wed, 15 Feb 2017 21:30:59 +0000
- To: public-tt@w3.org
palemieux has just created a new issue for https://github.com/w3c/ttml2: == Signaling HDR pixels in PNG for use with <image> == The TTML2 allow PNG images to be displayed. In order to allow the use of the `image` with HDR video (see #233 for additional background on HDR video), TTML2 should support PNG sources carrying HDR images as specified in the [attached](https://github.com/w3c/ttml2/files/778427/png_st2084_20170125.zip). The latter is intended to be compatible with current PNG implementations and uses existing PNG structures: - HDR pixels are carried PQ-encoded using full-range quantization - the profile name field of the iCCP chunk is used to signal the color system - implementations that do not recognize the magic profile names but support the iCCP chunk will process the image using an embedded ICC profile, which can evolve as the ICC standard evolves - implementations that do not recognize the iCCP chunk should display the image according to the cHRM and gAMA chunks - implementations that ignore iCCP, cHRM and gAMA chunks will still display the image - implementations that merely blit the PNG onto video with the same HDR colorspace, but without any color conversion, would end-up with an adequate image Please view or discuss this issue at https://github.com/w3c/ttml2/issues/244 using your GitHub account
Received on Wednesday, 15 February 2017 21:31:05 UTC