Fix AnnexB validation logic to work with encrypted content.

media/filters/h264_parser.h

Index: media/filters/h264_parser.h
diff --git a/media/filters/h264_parser.h b/media/filters/h264_parser.h
index 45020af61344b8228259bfc2a4868b1b7cfd8a9d..0da0bed7bcf7e63f049e8137957f87467fa5279f 100644
--- a/media/filters/h264_parser.h
+++ b/media/filters/h264_parser.h
@@ -13,10 +13,13 @@
 
 #include "base/basictypes.h"
 #include "media/base/media_export.h"
+#include "media/base/ranges.h"
 #include "media/filters/h264_bit_reader.h"
 
 namespace media {
 
+struct SubsampleEntry;
+
 // For explanations of each struct and its members, see H.264 specification
 // at http://www.itu.int/rec/T-REC-H.264.
 struct MEDIA_EXPORT H264NALU {
@@ -337,7 +340,11 @@ class MEDIA_EXPORT H264Parser {
   void Reset();
   // Set current stream pointer to |stream| of |stream_size| in bytes,
   // |stream| owned by caller.
+  // |subsamples| contains information about what parts of |stream| are
+  // encrypted.
   void SetStream(const uint8* stream, off_t stream_size);
+  void SetStream(const uint8* stream, off_t stream_size,
+                 const std::vector<SubsampleEntry>& subsamples);

[xhwang, 2014/07/10 06:23:01]

nit: The style guide doesn't encourage function overloading... how about
SetEncryptedStream?

[xhwang, 2014/07/10 06:23:01]

nit: Add include for vector.

[acolwell GONE FROM CHROMIUM, 2014/07/15 22:10:44]

Done.

[acolwell GONE FROM CHROMIUM, 2014/07/15 22:10:44]

Done.

 
   // Read the stream to find the next NALU, identify it and return
   // that information in |*nalu|. This advances the stream to the beginning
@@ -392,6 +399,11 @@ class MEDIA_EXPORT H264Parser {
   // - the size in bytes of the start code is returned in |*start_code_size|.
   bool LocateNALU(off_t* nalu_size, off_t* start_code_size);
 
+  // Wrapper for FindStartCode() that skips over start codes that
+  // may appear inside |encrypted_ranges_|.
+  bool FindNextStartCode(const uint8* data, off_t data_size,

[xhwang, 2014/07/10 06:23:01]

It's not obvious to know the difference b/w FindStartCode and FindNextStartCode
by looking at the function names. How about FindStartCodeInClearRanges?

[acolwell GONE FROM CHROMIUM, 2014/07/15 22:10:44]

Done.

+                         off_t* offset, off_t* start_code_size);
+
   // Exp-Golomb code parsing as specified in chapter 9.1 of the spec.
   // Read one unsigned exp-Golomb code from the stream and return in |*val|.
   Result ReadUE(int* val);
@@ -441,6 +453,8 @@ class MEDIA_EXPORT H264Parser {
   SPSById active_SPSes_;
   PPSById active_PPSes_;
 
+  Ranges<const uint8*> encrypted_ranges_;

[xhwang, 2014/07/10 06:23:01]

Since this range is only used for searching for start code, how about store a
|clear_ranges_| instead? Then the FindNextStartCode() function can be easier to
implement.

[acolwell GONE FROM CHROMIUM, 2014/07/15 22:10:44]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(H264Parser);
 };