| /********** |
| This library is free software; you can redistribute it and/or modify it under |
| the terms of the GNU Lesser General Public License as published by the |
| Free Software Foundation; either version 3 of the License, or (at your |
| option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.) |
| |
| This library is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for |
| more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this library; if not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved. |
| // A filter that breaks up an H263 video stream into frames. |
| // derived from MPEG4IP h263.c |
| // Author Benhard Feiten |
| |
| #ifndef _H263PLUS_VIDEO_STREAM_PARSER_HH |
| #define _H263PLUS_VIDEO_STREAM_PARSER_HH |
| |
| #ifndef _STREAM_PARSER_HH |
| #include "StreamParser.hh" |
| #endif |
| |
| |
| // Default timescale for H.263 (1000ms) |
| #define H263_TIMESCALE 1000 |
| |
| // Default H263 frame rate (30fps) |
| #define H263_BASIC_FRAME_RATE 30 |
| |
| // Minimum number of bytes needed to parse an H263 header |
| #define H263_REQUIRE_HEADER_SIZE_BYTES 5 |
| |
| // Number of bytes the start code requries |
| #define H263_STARTCODE_SIZE_BYTES 3 |
| |
| // This is the input buffer's size. It should contain |
| // 1 frame with the following start code |
| #define H263_BUFFER_SIZE 256 * 1024 |
| |
| // additionalBytesNeeded - indicates how many additional bytes are to be read |
| // from the next frame's header (over the 3 bytes that are already read). |
| #define ADDITIONAL_BYTES_NEEDED H263_REQUIRE_HEADER_SIZE_BYTES - H263_STARTCODE_SIZE_BYTES |
| |
| // The default max different (in %) betwqeen max and average bitrates |
| #define H263_DEFAULT_CBR_TOLERANCE 10 |
| |
| |
| |
| // The following structure holds information extracted from each frame's header: |
| typedef struct _H263INFO { |
| u_int8_t tr; // Temporal Reference, used in duration calculation |
| u_int16_t width; // Width of the picture |
| u_int16_t height; // Height of the picture |
| bool isSyncFrame; // Frame type (true = I frame = "sync" frame) |
| } H263INFO; |
| |
| typedef struct _MaxBitrate_CTX { |
| u_int32_t bitrateTable[H263_BASIC_FRAME_RATE];// Window of 1 second |
| u_int32_t windowBitrate; // The bitrate of the current window |
| u_int32_t maxBitrate; // The up-to-date maximum bitrate |
| u_int32_t tableIndex; // The next TR unit to update |
| } MaxBitrate_CTX; |
| |
| |
| class H263plusVideoStreamParser : public StreamParser { |
| |
| public: |
| H263plusVideoStreamParser( class H263plusVideoStreamFramer* usingSource, |
| FramedSource* inputSource); |
| |
| virtual ~H263plusVideoStreamParser(); |
| |
| void registerReadInterest(unsigned char* to, unsigned maxSize); |
| |
| unsigned parse(u_int64_t & currentDuration); // returns the size of the frame that was acquired, or 0 if none |
| unsigned numTruncatedBytes() const { return fNumTruncatedBytes; } // The number of truncated bytes (if any) |
| |
| |
| protected: |
| // H263plusVideoStreamFramer* usingSource() { |
| // return (H263plusVideoStreamFramer*)fUsingSource; |
| // } |
| void setParseState(); |
| |
| // void setParseState(H263plusParseState parseState); |
| |
| |
| private: |
| int parseH263Frame( ); |
| bool ParseShortHeader(u_int8_t *headerBuffer, H263INFO *outputInfoStruct); |
| void GetMaxBitrate( MaxBitrate_CTX *ctx, u_int32_t frameSize, u_int8_t frameTRDiff); |
| u_int64_t CalculateDuration(u_int8_t trDiff); |
| bool GetWidthAndHeight( u_int8_t fmt, u_int16_t *width, u_int16_t *height); |
| u_int8_t GetTRDifference( u_int8_t nextTR, u_int8_t currentTR); |
| |
| virtual void restoreSavedParserState(); |
| |
| protected: |
| class H263plusVideoStreamFramer* fUsingSource; |
| |
| unsigned char* fTo; |
| unsigned fMaxSize; |
| unsigned char* fStartOfFrame; |
| unsigned char* fSavedTo; |
| unsigned char* fLimit; |
| unsigned fNumTruncatedBytes; |
| unsigned fSavedNumTruncatedBytes; |
| |
| private: |
| H263INFO fNextInfo; // Holds information about the next frame |
| H263INFO fCurrentInfo; // Holds information about the current frame |
| MaxBitrate_CTX fMaxBitrateCtx; // Context for the GetMaxBitrate function |
| char fStates[3][256]; |
| u_int8_t fNextHeader[H263_REQUIRE_HEADER_SIZE_BYTES]; |
| |
| u_int32_t fnextTR; // The next frame's presentation time in TR units |
| u_int64_t fcurrentPT; // The current frame's presentation time in milli-seconds |
| |
| }; |
| |
| #endif |