Recognize codec id vp9.2 as VP9 profile 2

media/base/mime_util_internal.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/mime_util_internal.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ skipping 569 matching lines @@
         return true;
 
       // MediaPlayer only supports VP9 in WebM.
       return mime_type_lower_case == "video/webm";
     }
   }
 
   return false;
 }
 
 bool MimeUtil::StringToCodec(const std::string& mime_type_lower_case,

[ddorwin, 2016/12/08 02:08:01]

Checks for valid and support are spread out too much in this and other files. We
need to establish clear responsibilities and expectations.

For example, there should be a clear expectation that IsSupportedVideoConfig()
must be called after this function. (One could even argue that it should be
called from within this function if we are going to return "supported" and not
ambiguous.)

It might be better if we limit this function to actually extracting data from a
string and defer processing it to a separate function. Yes, we then need to
check the Codec in a switch statement, but the responsibilities will be much
clearer. This also means we'll need to add more output parameters to support
some of the longer codec strings, but we're going to need to do that to be able
to query the platform anyway.

We also have IsCodecSupported(), which calls IsCodecSupportedOnPlatform(). Thus,
we have multiple paths doing similar things.

I filed https://crbug.com/672327 to track this.

                              const std::string& codec_id,
                              Codec* codec,
                              bool* is_ambiguous,
                              VideoCodecProfile* out_profile,
                              uint8_t* out_level,
                              bool is_encrypted) const {
   DCHECK(out_profile);
   DCHECK(out_level);
   *out_profile = VIDEO_CODEC_PROFILE_UNKNOWN;
   *out_level = 0;
@@ skipping 10 matching lines @@
   // either VP9, H.264 or HEVC/H.265 codec ID because currently those are the
   // only ones that are not added to the |string_to_codec_map_| and require
   // parsing.
   if (ParseVp9CodecID(mime_type_lower_case, codec_id, out_profile, out_level)) {
     *codec = MimeUtil::VP9;
     switch (*out_profile) {
       case VP9PROFILE_PROFILE0:
         // Profile 0 should always be supported if VP9 is supported.
         *is_ambiguous = false;
         break;
+      case VP9PROFILE_PROFILE2:
+        *is_ambiguous = false;
+        break;
       default:
         // We don't know if the underlying platform supports these profiles.

[ddorwin, 2016/12/08 02:08:01]

This statement does not seem true anymore. IsSupportedVideoConfig() should
answer this. In that case, it would seem that we do not need the profile switch
statement here and (for now - until we support levels, etc.) VP9 is not
ambiguous. (The profile extraction code should reject anything that is not 0-3.)

This assumes that all IsSupportedVideoConfig() implementations are implemented
correctly (only accepting 0 and maybe 2), which should be the case. However,
given the proposed Chrome implementation, we should verify this.

See also https://crbug.com/672327.

         // Need to add platform level querying to get supported profiles
         // (crbug/604566).
         *is_ambiguous = true;
         break;
     }
     return true;
   }
 
   if (ParseAVCCodecId(codec_id, out_profile, out_level)) {
     *codec = MimeUtil::H264;
@@ skipping 100 matching lines @@
     const std::string& mime_type_lower_case,
     bool is_encrypted) const {
   Codec default_codec = Codec::INVALID_CODEC;
   if (!GetDefaultCodecLowerCase(mime_type_lower_case, &default_codec))
     return false;
   return IsCodecSupported(default_codec, mime_type_lower_case, is_encrypted);
 }
 
 }  // namespace internal
 }  // namespace media