Fix: Adding list of supported codecs for MP4 containers

net/base/mime_util.h

Index: net/base/mime_util.h
diff --git a/net/base/mime_util.h b/net/base/mime_util.h
index 6c943a7f7da83dc1f1e021c6db4578bfe7188621..3bb1f8932aede52afef9a2518b65f32e96ed55ca 100644
--- a/net/base/mime_util.h
+++ b/net/base/mime_util.h
@@ -94,12 +94,16 @@ NET_EXPORT void ParseCodecString(const std::string& codecs,
 // certain subset of codecs.
 NET_EXPORT bool IsStrictMediaMimeType(const std::string& mime_type);
 
+enum SupportsType { IsNotSupported, IsSupported, MayBeSupported };

[Ryan Sleevi, 2014/06/10 19:15:43]

1) Have you run git cl format on this?
2) Document

That is, as it reads now (and with the documentation below), this has the smell
of the infamous tri-state bool (
http://thedailywtf.com/Articles/What_Is_Truth_0x3f_.aspx )

Knowing that I'm not familiar with this exact details of media codecs, I have to
defer to the media/ OWNERs to make sure this is correct to them, but I would
suspect that:

// Indicates whether or not a given MIME type (and possible codec string) are
supported by the underlying platform.
enum SupportsType {
  // The underlying platform is known to support this MIME type.
  IsSupported,
  // The underlying platform is believed to support this MIME type,
  // but there may be additional limitations (eg: for some codecs,
  // only particular codec parameters, such as profiles, may be
  // supported).
  MayBeSupported,
  // The platform is known not to support the requested configuration (e.g. if
an unsupported MIME type or codec is supplied)
};

[amogh.bihani, 2014/06/11 11:32:41]

Done.

+
 // Check to see if a particular MIME type is in our list which only supports a
-// certain subset of codecs. Returns true if and only if all codecs are
-// supported for that specific MIME type, false otherwise. If this returns
-// false you will still need to check if the media MIME tpyes and codecs are
-// supported.
-NET_EXPORT bool IsSupportedStrictMediaMimeType(
+// certain subset of codecs.
+// * Returns IsSupported if and only if all the codecs are supported for that
+//   specific MIME type.
+// * Returns MayBeSupported if codecs paramter is empty or has a profile

[Ryan Sleevi, 2014/06/10 19:15:43]

typo: paramter

[amogh.bihani, 2014/06/11 11:32:41]

rectified.

+//   parameter which can't be decided whether it is supported or not.
+// * Returns IsNotSupported if none of the aforementioned conditions are met.

[Ryan Sleevi, 2014/06/10 19:15:43]

With the above comment for SupportsType, let's build out this comment

// Checks the |mime_type| and |codecs| against the MIME types known
// to support only a particular subset of codecs/parameters.
// * Returns IsSupported if the |mime_type| is supported and supports
//   all of the codecs within |codecs|
// * Returns MayBeSupported if the |mime_type| is supported and is
//   known to support only a subset of codecs, but |codecs| was empty.
//   Also returned if a codec is supported, but additional codec
//   parameters were supplied (such as a profile) for which support
//   cannot be decided.
// * Returns IsNotSupported in all other cases.


That said, as I read both your comment and the attempted reword, what happens if
|codecs| contains (X.profile and Y), where Y is not supported, but X.profile is?
MayBeSupported or IsNotSupported?

My *guess* is that it's IsNotSupported - that is, MayBeSupported is only
returned if *all* codecs in |codec| are supported, but at least one codec has a
parameter which support cannot be conclusively determined.

[amogh.bihani, 2014/06/11 11:32:41]

Done.

+NET_EXPORT SupportsType IsSupportedStrictMediaMimeType(
     const std::string& mime_type,
     const std::vector<std::string>& codecs);