modules/rtp_rtcp/source/rtp_format_vp8.h - src/webrtc - Git at Google

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 /*
  * This file contains the declaration of the VP8 packetizer class.
  * A packetizer object is created for each encoded video frame. The
  * constructor is called with the payload data and size,
  * together with the fragmentation information and a packetizer mode
  * of choice. Alternatively, if no fragmentation info is available, the
  * second constructor can be used with only payload data and size; in that
  * case the mode kEqualSize is used.
  *
  * After creating the packetizer, the method NextPacket is called
  * repeatedly to get all packets for the frame. The method returns
  * false as long as there are more packets left to fetch.
  */

 #ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_FORMAT_VP8_H_
 #define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_FORMAT_VP8_H_

 #include <queue>
 #include <vector>

 #include "modules/interface/module_common_types.h"
 #include "system_wrappers/interface/constructor_magic.h"
 #include "typedefs.h"  // NOLINT(build/include)

 namespace webrtc {

 enum VP8PacketizerMode {
   kStrict = 0,  // Split partitions if too large;
                 // never aggregate, balance size.
   kAggregate,   // Split partitions if too large; aggregate whole partitions.
   kEqualSize,   // Split entire payload without considering partition limits.
                 // This will produce equal size packets for the whole frame.
   kNumModes,
 };

 // Packetizer for VP8.
 class RtpFormatVp8 {
  public:
   // Initialize with payload from encoder and fragmentation info.
   // The payload_data must be exactly one encoded VP8 frame.
   RtpFormatVp8(const WebRtc_UWord8* payload_data,
                WebRtc_UWord32 payload_size,
                const RTPVideoHeaderVP8& hdr_info,
                int max_payload_len,
                const RTPFragmentationHeader& fragmentation,
                VP8PacketizerMode mode);

   // Initialize without fragmentation info. Mode kEqualSize will be used.
   // The payload_data must be exactly one encoded VP8 frame.
   RtpFormatVp8(const WebRtc_UWord8* payload_data,
                WebRtc_UWord32 payload_size,
                const RTPVideoHeaderVP8& hdr_info,
                int max_payload_len);

   // Get the next payload with VP8 payload header.
   // max_payload_len limits the sum length of payload and VP8 payload header.
   // buffer is a pointer to where the output will be written.
   // bytes_to_send is an output variable that will contain number of bytes
   // written to buffer. Parameter last_packet is true for the last packet of
   // the frame, false otherwise (i.e., call the function again to get the
   // next packet).
   // For the kStrict and kAggregate mode: returns the partition index from which
   // the first payload byte in the packet is taken, with the first partition
   // having index 0; returns negative on error.
   // For the kEqualSize mode: returns 0 on success, return negative on error.
   int NextPacket(WebRtc_UWord8* buffer,
                  int* bytes_to_send,
                  bool* last_packet);

  private:
   typedef struct {
     int payload_start_pos;
     int size;
     bool first_fragment;
     int first_partition_ix;
   } InfoStruct;
   typedef std::queue<InfoStruct> InfoQueue;
   enum AggregationMode {
     kAggrNone = 0,    // No aggregation.
     kAggrPartitions,  // Aggregate intact partitions.
     kAggrFragments    // Aggregate intact and fragmented partitions.
   };

   static const AggregationMode aggr_modes_[kNumModes];
   static const bool balance_modes_[kNumModes];
   static const bool separate_first_modes_[kNumModes];
   static const int kXBit        = 0x80;
   static const int kNBit        = 0x20;
   static const int kSBit        = 0x10;
   static const int kPartIdField = 0x0F;
   static const int kKeyIdxField = 0x1F;
   static const int kIBit        = 0x80;
   static const int kLBit        = 0x40;
   static const int kTBit        = 0x20;
   static const int kKBit        = 0x10;
   static const int kYBit        = 0x20;

   // Calculate size of next chunk to send. Returns 0 if none can be sent.
   int CalcNextSize(int max_payload_len, int remaining_bytes,
                    bool split_payload) const;

   // Calculate all packet sizes and load to packet info queue.
   int GeneratePackets();

   // Calculate all packet sizes using Vp8PartitionAggregator and load to packet
   // info queue.
   int GeneratePacketsBalancedAggregates();

   // Helper function to GeneratePacketsBalancedAggregates(). Find all
   // continuous sets of partitions smaller than the max payload size (not
   // max_size), and aggregate them into balanced packets. The result is written
   // to partition_vec, which is of the same length as the number of partitions.
   // A value of -1 indicates that the partition is too large and must be split.
   // Aggregates are numbered 0, 1, 2, etc. For each set of small partitions,
   // the aggregate numbers restart at 0. Output values min_size and max_size
   // will hold the smallest and largest resulting aggregates (i.e., not counting
   // those that must be split).
   void AggregateSmallPartitions(std::vector<int>* partition_vec,
                                 int* min_size,
                                 int* max_size);

   // Insert packet into packet queue.
   void QueuePacket(int start_pos,
                    int packet_size,
                    int first_partition_in_packet,
                    bool start_on_new_fragment);

   // Write the payload header and copy the payload to the buffer.
   // The info in packet_info determines which part of the payload is written
   // and what to write in the header fields.
   int WriteHeaderAndPayload(const InfoStruct& packet_info,
                             WebRtc_UWord8* buffer,
                             int buffer_length) const;


   // Write the X field and the appropriate extension fields to buffer.
   // The function returns the extension length (including X field), or -1
   // on error.
   int WriteExtensionFields(WebRtc_UWord8* buffer, int buffer_length) const;

   // Set the I bit in the x_field, and write PictureID to the appropriate
   // position in buffer. The function returns 0 on success, -1 otherwise.
   int WritePictureIDFields(WebRtc_UWord8* x_field, WebRtc_UWord8* buffer,
                            int buffer_length, int* extension_length) const;

   // Set the L bit in the x_field, and write Tl0PicIdx to the appropriate
   // position in buffer. The function returns 0 on success, -1 otherwise.
   int WriteTl0PicIdxFields(WebRtc_UWord8* x_field, WebRtc_UWord8* buffer,
                            int buffer_length, int* extension_length) const;

   // Set the T and K bits in the x_field, and write TID, Y and KeyIdx to the
   // appropriate position in buffer. The function returns 0 on success,
   // -1 otherwise.
   int WriteTIDAndKeyIdxFields(WebRtc_UWord8* x_field, WebRtc_UWord8* buffer,
                               int buffer_length, int* extension_length) const;

   // Write the PictureID from codec_specific_info_ to buffer. One or two
   // bytes are written, depending on magnitude of PictureID. The function
   // returns the number of bytes written.
   int WritePictureID(WebRtc_UWord8* buffer, int buffer_length) const;

   // Calculate and return length (octets) of the variable header fields in
   // the next header (i.e., header length in addition to vp8_header_bytes_).
   int PayloadDescriptorExtraLength() const;

   // Calculate and return length (octets) of PictureID field in the next
   // header. Can be 0, 1, or 2.
   int PictureIdLength() const;

   // Check whether each of the optional fields will be included in the header.
   bool XFieldPresent() const;
   bool TIDFieldPresent() const;
   bool KeyIdxFieldPresent() const;
   bool TL0PicIdxFieldPresent() const;
   bool PictureIdPresent() const { return (PictureIdLength() > 0); }

   const WebRtc_UWord8* payload_data_;
   const int payload_size_;
   RTPFragmentationHeader part_info_;
   const int vp8_fixed_payload_descriptor_bytes_;  // Length of VP8 payload
                                                   // descriptors's fixed part.
   const AggregationMode aggr_mode_;
   const bool balance_;
   const bool separate_first_;
   const RTPVideoHeaderVP8 hdr_info_;
   const int num_partitions_;
   const int max_payload_len_;
   InfoQueue packets_;
   bool packets_calculated_;

   DISALLOW_COPY_AND_ASSIGN(RtpFormatVp8);
 };

 }  // namespace

 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_FORMAT_VP8_H_
	/*
	* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	/*
	* This file contains the declaration of the VP8 packetizer class.
	* A packetizer object is created for each encoded video frame. The
	* constructor is called with the payload data and size,
	* together with the fragmentation information and a packetizer mode
	* of choice. Alternatively, if no fragmentation info is available, the
	* second constructor can be used with only payload data and size; in that
	* case the mode kEqualSize is used.
	*
	* After creating the packetizer, the method NextPacket is called
	* repeatedly to get all packets for the frame. The method returns
	* false as long as there are more packets left to fetch.
	*/

	#ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_FORMAT_VP8_H_
	#define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_FORMAT_VP8_H_

	#include <queue>
	#include <vector>

	#include "modules/interface/module_common_types.h"
	#include "system_wrappers/interface/constructor_magic.h"
	#include "typedefs.h" // NOLINT(build/include)

	namespace webrtc {

	enum VP8PacketizerMode {
	kStrict = 0, // Split partitions if too large;
	// never aggregate, balance size.
	kAggregate, // Split partitions if too large; aggregate whole partitions.
	kEqualSize, // Split entire payload without considering partition limits.
	// This will produce equal size packets for the whole frame.
	kNumModes,
	};

	// Packetizer for VP8.
	class RtpFormatVp8 {
	public:
	// Initialize with payload from encoder and fragmentation info.
	// The payload_data must be exactly one encoded VP8 frame.
	RtpFormatVp8(const WebRtc_UWord8* payload_data,
	WebRtc_UWord32 payload_size,
	const RTPVideoHeaderVP8& hdr_info,
	int max_payload_len,
	const RTPFragmentationHeader& fragmentation,
	VP8PacketizerMode mode);

	// Initialize without fragmentation info. Mode kEqualSize will be used.
	// The payload_data must be exactly one encoded VP8 frame.
	RtpFormatVp8(const WebRtc_UWord8* payload_data,
	WebRtc_UWord32 payload_size,
	const RTPVideoHeaderVP8& hdr_info,
	int max_payload_len);

	// Get the next payload with VP8 payload header.
	// max_payload_len limits the sum length of payload and VP8 payload header.
	// buffer is a pointer to where the output will be written.
	// bytes_to_send is an output variable that will contain number of bytes
	// written to buffer. Parameter last_packet is true for the last packet of
	// the frame, false otherwise (i.e., call the function again to get the
	// next packet).
	// For the kStrict and kAggregate mode: returns the partition index from which
	// the first payload byte in the packet is taken, with the first partition
	// having index 0; returns negative on error.
	// For the kEqualSize mode: returns 0 on success, return negative on error.
	int NextPacket(WebRtc_UWord8* buffer,
	int* bytes_to_send,
	bool* last_packet);

	private:
	typedef struct {
	int payload_start_pos;
	int size;
	bool first_fragment;
	int first_partition_ix;
	} InfoStruct;
	typedef std::queue<InfoStruct> InfoQueue;
	enum AggregationMode {
	kAggrNone = 0, // No aggregation.
	kAggrPartitions, // Aggregate intact partitions.
	kAggrFragments // Aggregate intact and fragmented partitions.
	};

	static const AggregationMode aggr_modes_[kNumModes];
	static const bool balance_modes_[kNumModes];
	static const bool separate_first_modes_[kNumModes];
	static const int kXBit = 0x80;
	static const int kNBit = 0x20;
	static const int kSBit = 0x10;
	static const int kPartIdField = 0x0F;
	static const int kKeyIdxField = 0x1F;
	static const int kIBit = 0x80;
	static const int kLBit = 0x40;
	static const int kTBit = 0x20;
	static const int kKBit = 0x10;
	static const int kYBit = 0x20;

	// Calculate size of next chunk to send. Returns 0 if none can be sent.
	int CalcNextSize(int max_payload_len, int remaining_bytes,
	bool split_payload) const;

	// Calculate all packet sizes and load to packet info queue.
	int GeneratePackets();

	// Calculate all packet sizes using Vp8PartitionAggregator and load to packet
	// info queue.
	int GeneratePacketsBalancedAggregates();

	// Helper function to GeneratePacketsBalancedAggregates(). Find all
	// continuous sets of partitions smaller than the max payload size (not
	// max_size), and aggregate them into balanced packets. The result is written
	// to partition_vec, which is of the same length as the number of partitions.
	// A value of -1 indicates that the partition is too large and must be split.
	// Aggregates are numbered 0, 1, 2, etc. For each set of small partitions,
	// the aggregate numbers restart at 0. Output values min_size and max_size
	// will hold the smallest and largest resulting aggregates (i.e., not counting
	// those that must be split).
	void AggregateSmallPartitions(std::vector<int>* partition_vec,
	int* min_size,
	int* max_size);

	// Insert packet into packet queue.
	void QueuePacket(int start_pos,
	int packet_size,
	int first_partition_in_packet,
	bool start_on_new_fragment);

	// Write the payload header and copy the payload to the buffer.
	// The info in packet_info determines which part of the payload is written
	// and what to write in the header fields.
	int WriteHeaderAndPayload(const InfoStruct& packet_info,
	WebRtc_UWord8* buffer,
	int buffer_length) const;


	// Write the X field and the appropriate extension fields to buffer.
	// The function returns the extension length (including X field), or -1
	// on error.
	int WriteExtensionFields(WebRtc_UWord8* buffer, int buffer_length) const;

	// Set the I bit in the x_field, and write PictureID to the appropriate
	// position in buffer. The function returns 0 on success, -1 otherwise.
	int WritePictureIDFields(WebRtc_UWord8* x_field, WebRtc_UWord8* buffer,
	int buffer_length, int* extension_length) const;

	// Set the L bit in the x_field, and write Tl0PicIdx to the appropriate
	// position in buffer. The function returns 0 on success, -1 otherwise.
	int WriteTl0PicIdxFields(WebRtc_UWord8* x_field, WebRtc_UWord8* buffer,
	int buffer_length, int* extension_length) const;

	// Set the T and K bits in the x_field, and write TID, Y and KeyIdx to the
	// appropriate position in buffer. The function returns 0 on success,
	// -1 otherwise.
	int WriteTIDAndKeyIdxFields(WebRtc_UWord8* x_field, WebRtc_UWord8* buffer,
	int buffer_length, int* extension_length) const;

	// Write the PictureID from codec_specific_info_ to buffer. One or two
	// bytes are written, depending on magnitude of PictureID. The function
	// returns the number of bytes written.
	int WritePictureID(WebRtc_UWord8* buffer, int buffer_length) const;

	// Calculate and return length (octets) of the variable header fields in
	// the next header (i.e., header length in addition to vp8_header_bytes_).
	int PayloadDescriptorExtraLength() const;

	// Calculate and return length (octets) of PictureID field in the next
	// header. Can be 0, 1, or 2.
	int PictureIdLength() const;

	// Check whether each of the optional fields will be included in the header.
	bool XFieldPresent() const;
	bool TIDFieldPresent() const;
	bool KeyIdxFieldPresent() const;
	bool TL0PicIdxFieldPresent() const;
	bool PictureIdPresent() const { return (PictureIdLength() > 0); }

	const WebRtc_UWord8* payload_data_;
	const int payload_size_;
	RTPFragmentationHeader part_info_;
	const int vp8_fixed_payload_descriptor_bytes_; // Length of VP8 payload
	// descriptors's fixed part.
	const AggregationMode aggr_mode_;
	const bool balance_;
	const bool separate_first_;
	const RTPVideoHeaderVP8 hdr_info_;
	const int num_partitions_;
	const int max_payload_len_;
	InfoQueue packets_;
	bool packets_calculated_;

	DISALLOW_COPY_AND_ASSIGN(RtpFormatVp8);
	};

	} // namespace

	#endif // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_FORMAT_VP8_H_