Mpeg2 TS stream parser for media source.

media/mp2t/es_parser_h264.h

+// Copyright (c) 2013 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.
+
+#ifndef MEDIA_MP2T_ES_PARSER_H264_H_
+#define MEDIA_MP2T_ES_PARSER_H264_H_
+
+#include <list>
+#include <utility>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/time/time.h"
+#include "media/base/byte_queue.h"
+#include "media/base/video_decoder_config.h"
+#include "media/mp2t/es_parser.h"
+
+namespace media {
+class BitReader;
+class StreamParserBuffer;
+}
+
+namespace media {
+namespace mp2t {
+
+// Remark:
+// In this h264 parser, frame splitting is based on AUD nals.
+// Mpeg2 TS spec: "2.14 Carriage of Rec. ITU-T H.264 | ISO/IEC 14496-10 video"
+// "Each AVC access unit shall contain an access unit delimiter NAL Unit;"
+//
+class EsParserH264 : public EsParser {
+ public:
+  typedef base::Callback<void(const VideoDecoderConfig&)> NewVideoConfigCB;
+
+  EsParserH264(const NewVideoConfigCB& new_video_config_cb,
+               const EmitBufferCB& emit_buffer_cb);
+  virtual ~EsParserH264();
+
+  // EsParser implementation.
+  virtual bool Parse(const uint8* buf, int size,
+                     base::TimeDelta pts,
+                     base::TimeDelta dts) OVERRIDE;
+  virtual void Flush() OVERRIDE;
+  virtual void Reset() OVERRIDE;
+
+ private:
+  struct TimingDesc {
+    base::TimeDelta dts;
+    base::TimeDelta pts;
+  };
+
+  // H264 parser.
+  // It resumes parsing from byte position |es_pos_|.
+  bool ParseInternal();
+
+  // Emit a frame if a frame has been started earlier.
+  void EmitFrameIfNeeded(int next_aud_pos);
+
+  // Start a new frame.
+  // Note: if aud_pos < 0, clear the current frame.
+  void StartFrame(int aud_pos);
+
+  // Discard |nbytes| of ES from the ES byte queue.
+  void DiscardEs(int nbytes);
+
+  // Parse a NAL / SPS.
+  // Returns true if successful (compliant bitstream).
+  bool NalParser(const uint8* buf, int size);
+  bool ProcessSPS(const uint8* buf, int size);
+
+  // Callbacks to pass the stream configuration and the frames.
+  NewVideoConfigCB new_video_config_cb_;
+  EmitBufferCB emit_buffer_cb_;
+
+  // Bytes of the ES stream that have not been emitted yet.
+  ByteQueue es_byte_queue_;
+  std::list<std::pair<int, TimingDesc> > timing_desc_list_;
+
+  // H264 parser state.
+  // Note: |current_access_unit_pos_| is pointing to an annexB syncword
+  // while |current_nal_pos_| is pointing to the NAL unit
+  // (i.e. does not include the annexB syncword).
+  int es_pos_;
+  int current_nal_pos_;
+  int current_access_unit_pos_;
+  bool is_key_frame_;
+
+  // Last video decoder config.
+  VideoDecoderConfig last_video_decoder_config_;
+};
+
+}  // namespace mp2t
+}  // namespace media
+
+#endif
+