Mpeg2 TS stream parser for media source.

media/mpeg2/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_MPEG2_ES_PARSER_H264_H_
+#define MEDIA_MPEG2_ES_PARSER_H264_H_
+
+#include <list>
+#include <utility>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "base/time/time.h"
+#include "media/base/byte_queue.h"
+#include "media/mpeg2/es_parser.h"
+
+namespace media {
+class BitReader;
+class VideoDecoderConfig;
+class StreamParserBuffer;
+}
+
+namespace media {
+namespace mpeg2ts {
+
+// 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;
+  typedef base::Callback<void(scoped_refptr<StreamParserBuffer>)> EmitBufferCB;
+
+  EsParserH264(NewVideoConfigCB new_video_config_cb,
+               EmitBufferCB emit_buffer_cb);
+  virtual ~EsParserH264();
+
+  // EsParser implementation.
+  virtual void Parse(const uint8* buf, int size,
+                     base::TimeDelta pts,
+                     base::TimeDelta dts) OVERRIDE;
+  virtual void Flush() OVERRIDE;
+
+ private:
+  enum NalUnitType {
+    kNalUnitTypeInvalid = -1,
+    kNalUnitTypeNonIdrSlice = 1,
+    kNalUnitTypeIdrSlice = 5,
+    kNalUnitTypeSPS = 7,
+    kNalUnitTypePPS = 8,
+    kNalUnitTypeAUD = 9,
+  };
+
+  struct NalDesc {
+    // Position of the NAL start code.
+    int position;
+    NalUnitType nal_unit_type;
+  };
+  typedef std::list<NalDesc> NalDescList;
+
+  struct TimingDesc {
+    base::TimeDelta dts;
+    base::TimeDelta pts;
+  };
+
+
+  void FindNals(const uint8* buf, int size);
+
+  void FindAccessUnits(std::list<NalDescList::iterator>* access_unit_list);
+
+  // Emit a frame whose first NAL is given by |cur_frame|.
+  // The frame includes all the NALs located between |cur_frame|
+  // and |nxt_frame| (not included).
+  void EmitFrame(NalDescList::iterator cur_frame,
+                 NalDescList::iterator nxt_frame,
+                 int nxt_frame_position);
+
+  void DiscardEs(int nbytes);
+
+  void NalParser(const uint8* buf, int size);
+
+  // Parse a SPS / Slice layer.
+  // Returns true if successful (compliant bitstream).
+  bool ProcessSPS(const uint8* buf, int size);
+  bool ProcessSliceLayer(const uint8* buf, int size);
+
+  // Helper function to read an unsigned exp-golomb value.
+  // TODO(damienv): should be part of the BitReader class.
+  bool ReadBitsExpGolomb(BitReader* bit_reader, uint32* exp_golomb_value);
+
+  // Bytes of the ES stream that have not been emitted yet.
+  ByteQueue es_byte_queue_;
+  std::list<std::pair<int, TimingDesc> > timing_desc_list_;
+
+  // NAL segmentation.
+  NalDescList nal_desc_list_;
+  int nal_es_pos_;
+
+  // Callbacks to pass the stream configuration and the frames.
+  NewVideoConfigCB new_video_config_cb_;
+  EmitBufferCB emit_buffer_cb_;
+
+  // Last video decoder config.
+  bool is_video_config_known_;
+  int profile_idc_;
+  int level_idc_;
+  uint32 pic_width_in_mbs_minus1_;
+  uint32 pic_height_in_map_units_minus1_;
+};
+
+}  // namespace mpeg2ts
+}  // namespace media
+
+#endif
+