diff --git a/index.bs b/index.bs index a1ac372..5af5c60 100644 --- a/index.bs +++ b/index.bs @@ -103,43 +103,18 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypte This section is non-normative
- This specification relies on exposing the following sets of properties: -
- An API to query the user agent with regards to the decoding and - encoding abilities of the device based on information such as the - codecs, profile, resolution, bitrates, etc. The API exposes - information such as whether the playback should be smooth and power - efficient. -
-- The intent of purposes of the decoding capabilities API is to provide - a powerful replacement to API such as - {{MediaSource/isTypeSupported()}} or - {{HTMLMediaElement/canPlayType()}} which are vague and mostly help the - callers to know if something can not be decoded but not how well it - should perform. -
-- Better information about the display properties such as supported - color gamut or dynamic range abilities in order to pick the right - content for the display and avoid providing HDR content to an SDR - display. -
-- Real time feedback about the playback so an adaptative streaming can - alter the quality of the content based on actual user perceived - quality. Such information will allow websites to react to a pick of - CPU/GPU usage in real time. It is expected that this will be tackled - as part of the [[media-playback-quality]] specification. -
-+ This specification focuses on encoding and decoding capabilities. + It is expected to be used with other web APIs that provide information about + the display properties, such as supported color gamut or dynamic range capabilities, + which enable web applications to pick the right content for the display and to, + for example, avoid providing HDR content to an SDR display.
@@ -174,7 +149,7 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypteThe input to the decoding capabilities is represented by a - {{MediaDecodingConfiguration}} dictionary and the input of the encoding + {{MediaDecodingConfiguration}} dictionary and the input to the encoding capabilities by a {{MediaEncodingConfiguration}} dictionary.
@@ -241,7 +216,7 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypte A {{MediaDecodingConfiguration}} has three types:
The bitrate member - represents the number of average bitrate of the audio track. The bitrate + represents the average bitrate of the audio track. The bitrate is the number of bits used to encode a second of the audio track.
The samplerate - represents the samplerate of the audio track in. The samplerate is the - number of samples of audio carried per second. samplerate is only + member represents the sample rate of the audio track. The sample rate + is the number of samples of audio carried per second. samplerate is only applicable to the decoding types {{media-source}}, {{file}}, and {{MediaDecodingType/webrtc}} and the encoding type {{MediaEncodingType/webrtc}}. @@ -961,7 +936,7 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypte Document.
config.keySystemConfiguration.keySystem
+ Let implementation be the implementation of config.keySystemConfiguration.keySystem
.
- config.keySystemConfiguration.audio.robustness
+ config.keySystemConfiguration.audio.robustness.
- config.keySystemConfiguration.audio.encryptionScheme
+ config.keySystemConfiguration.audio.encryptionScheme.
- config.keySystemConfiguration.video.encryptionScheme
+ config.keySystemConfiguration.video.encryptionScheme.
- HDR detection is more nuanced. Adding colorGamut, transferFunction, and - hdrMetadataType has the potential to add significant entropy. However, + HDR detection is more nuanced. Adding {{colorGamut}}, {{transferFunction}}, and + {{hdrMetadataType}} has the potential to add significant entropy. However, for UAs whose decoders are implemented in software and therefore whose capabilities are fixed across devices, this feature adds no effective entropy. Additionally, for many cases, devices tend to fall into large @@ -1212,7 +1187,7 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypte
If an implementation wishes to implement a fingerprint-proof version of this specification, it would be recommended to fake a given set of - capabilities (ie. decode up to 1080p VP9, etc.) instead of returning + capabilities (i.e., decode up to 1080p VP9, etc.) instead of returning always yes or always no as the latter approach could considerably degrade the user's experience. Another mitigation could be to limit these Web APIs to top-level browsing contexts. Yet another is to use a @@ -1372,7 +1347,7 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypte