EME contentType checks DolbyVision

components/cdm/browser/cdm_message_filter_android.cc

Index: components/cdm/browser/cdm_message_filter_android.cc
diff --git a/components/cdm/browser/cdm_message_filter_android.cc b/components/cdm/browser/cdm_message_filter_android.cc
index 849b716a379d6884a38d0eeb3f56be32ca7873f2..4d7e99d07e06bb3be97a1b5487c25a4b6a96d56c 100644
--- a/components/cdm/browser/cdm_message_filter_android.cc
+++ b/components/cdm/browser/cdm_message_filter_android.cc
@@ -41,6 +41,12 @@ const CodecInfo<media::VideoCodec> kVideoCodecsToQuery[] = {
 #if BUILDFLAG(ENABLE_HEVC_DEMUXING)
     {media::EME_CODEC_MP4_HEVC, media::kCodecHEVC, "video/mp4"},
 #endif
+#if BUILDFLAG(ENABLE_DOLBY_VISION_DEMUXING)

[chcunningham, 2017/04/17 16:14:24]

I don't think this is sufficient to actually check demuxing capabilities of a
given key system. Below, we will simply pass the same "video/mp4" to
MediaDrmBridge::IsKeySystemSupportedWithType for all of [MP4_HEVC, DV_AVC,
DV_HEVC]. But the reality is demuxers need special logic to actually parse HEVC
that they do not need for parsing a vanilla "video/mp4; codecs='avc'". For
example, see our special HEVC demuxing logic in
https://cs.chromium.org/chromium/src/media/formats/mp4/box_definitions.cc?l=753
 
If I read it correctly, this problem extends to the existing code that checks
for MP4_HEVC even without dolby vision.

It seems like this  may be a limitation of the underlying android API:
https://developer.android.com/reference/android/media/MediaDrm.html#isCryptoS...,
java.lang.String)

Please reach out to MediaDrm folks to get a sense for whether (and for what
versions)  HEVC demuxing is supported on given key systems. We may need plumb an
additional signal that this is "video/mp4" *for hevc* and do some API version
checking to give the correct answer.

[yucliu1, 2017/04/18 00:13:02]

I b
I think the 'special logic' (profile, level, etc) should be handled by MimeUtil
checks before entering here, also 'CanDecode' performs some check on whether the
platform supports decoding the vanilla type.

+xhwang to confirm this.

+    {media::EME_CODEC_MP4_DV_AVC, media::kCodecDolbyVision, "video/mp4"},
+#if BUILDFLAG(ENABLE_HEVC_DEMUXING)
+    {media::EME_CODEC_MP4_DV_HEVC, media::kCodecDolbyVision, "video/mp4"},
+#endif
+#endif
 #endif  // BUILDFLAG(USE_PROPRIETARY_CODECS)
 };