479 lines
16 KiB
C++
479 lines
16 KiB
C++
/// \file flv_tag.cpp
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/// Holds all code for the FLV namespace.
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#include "flv_tag.h"
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#include "rtmpchunks.h"
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#include <stdio.h> //for Tag::FileLoader
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#include <unistd.h> //for Tag::FileLoader
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#include <fcntl.h> //for Tag::FileLoader
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#include <stdlib.h> //malloc
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#include <string.h> //memcpy
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/// Holds the last FLV header parsed.
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/// Defaults to a audio+video header on FLV version 0x01 if no header received yet.
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char FLV::Header[13] = {'F', 'L', 'V', 0x01, 0x05, 0, 0, 0, 0x09, 0, 0, 0, 0};
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bool FLV::Parse_Error = false; ///< This variable is set to true if a problem is encountered while parsing the FLV.
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std::string FLV::Error_Str = "";
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/// Checks a FLV Header for validness. Returns true if the header is valid, false
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/// if the header is not. Not valid can mean:
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/// - Not starting with the string "FLV".
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/// - The DataOffset is not 9 bytes.
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/// - The PreviousTagSize is not 0 bytes.
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///
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/// Note that we see PreviousTagSize as part of the FLV header, not part of the tag header!
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bool FLV::check_header(char * header){
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if (header[0] != 'F') return false;
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if (header[1] != 'L') return false;
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if (header[2] != 'V') return false;
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if (header[5] != 0) return false;
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if (header[6] != 0) return false;
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if (header[7] != 0) return false;
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if (header[8] != 0x09) return false;
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if (header[9] != 0) return false;
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if (header[10] != 0) return false;
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if (header[11] != 0) return false;
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if (header[12] != 0) return false;
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return true;
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}//FLV::check_header
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/// Checks the first 3 bytes for the string "FLV". Implementing a basic FLV header check,
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/// returning true if it is, false if not.
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bool FLV::is_header(char * header){
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if (header[0] != 'F') return false;
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if (header[1] != 'L') return false;
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if (header[2] != 'V') return false;
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return true;
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}//FLV::is_header
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/// True if this media type requires init data.
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/// Will always return false if the tag type is not 0x08 or 0x09.
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/// Returns true for H263, AVC (H264), AAC.
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/// \todo Check if MP3 does or does not require init data...
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bool FLV::Tag::needsInitData(){
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switch (data[0]){
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case 0x09:
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switch (data[11] & 0x0F){
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case 2: return true; break;//H263 requires init data
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case 7: return true; break;//AVC requires init data
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default: return false; break;//other formats do not
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}
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break;
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case 0x08:
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switch (data[11] & 0xF0){
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case 0x20: return false; break;//MP3 does not...? Unsure.
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case 0xA0: return true; break;//AAC requires init data
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case 0xE0: return false; break;//MP38kHz does not...?
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default: return false; break;//other formats do not
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}
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break;
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}
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return false;//only audio/video can require init data
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}
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/// True if current tag is init data for this media type.
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bool FLV::Tag::isInitData(){
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switch (data[0]){
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case 0x09:
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switch (data[11] & 0xF0){
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case 0x50: return true; break;
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}
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if ((data[11] & 0x0F) == 7){
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switch (data[12]){
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case 0: return true; break;
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}
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}
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break;
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case 0x08:
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if ((data[12] == 0) && ((data[11] & 0xF0) == 0xA0)){
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return true;
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}
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break;
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}
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return false;
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}
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/// Returns a std::string describing the tag in detail.
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/// The string includes information about whether the tag is
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/// audio, video or metadata, what encoding is used, and the details
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/// of the encoding itself.
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std::string FLV::Tag::tagType(){
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std::string R = "";
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switch (data[0]){
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case 0x09:
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switch (data[11] & 0x0F){
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case 1: R += "JPEG"; break;
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case 2: R += "H263"; break;
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case 3: R += "ScreenVideo1"; break;
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case 4: R += "VP6"; break;
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case 5: R += "VP6Alpha"; break;
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case 6: R += "ScreenVideo2"; break;
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case 7: R += "AVC"; break;
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default: R += "unknown"; break;
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}
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R += " video ";
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switch (data[11] & 0xF0){
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case 0x10: R += "keyframe"; break;
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case 0x20: R += "iframe"; break;
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case 0x30: R += "disposableiframe"; break;
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case 0x40: R += "generatedkeyframe"; break;
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case 0x50: R += "videoinfo"; break;
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}
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if ((data[11] & 0x0F) == 7){
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switch (data[12]){
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case 0: R += " header"; break;
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case 1: R += " NALU"; break;
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case 2: R += " endofsequence"; break;
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}
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}
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break;
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case 0x08:
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switch (data[11] & 0xF0){
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case 0x00: R += "linear PCM PE"; break;
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case 0x10: R += "ADPCM"; break;
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case 0x20: R += "MP3"; break;
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case 0x30: R += "linear PCM LE"; break;
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case 0x40: R += "Nelly16kHz"; break;
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case 0x50: R += "Nelly8kHz"; break;
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case 0x60: R += "Nelly"; break;
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case 0x70: R += "G711A-law"; break;
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case 0x80: R += "G711mu-law"; break;
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case 0x90: R += "reserved"; break;
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case 0xA0: R += "AAC"; break;
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case 0xB0: R += "Speex"; break;
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case 0xE0: R += "MP38kHz"; break;
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case 0xF0: R += "DeviceSpecific"; break;
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default: R += "unknown"; break;
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}
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switch (data[11] & 0x0C){
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case 0x0: R += " 5.5kHz"; break;
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case 0x4: R += " 11kHz"; break;
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case 0x8: R += " 22kHz"; break;
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case 0xC: R += " 44kHz"; break;
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}
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switch (data[11] & 0x02){
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case 0: R += " 8bit"; break;
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case 2: R += " 16bit"; break;
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}
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switch (data[11] & 0x01){
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case 0: R += " mono"; break;
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case 1: R += " stereo"; break;
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}
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R += " audio";
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if ((data[12] == 0) && ((data[11] & 0xF0) == 0xA0)){
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R += " initdata";
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}
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break;
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case 0x12:
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R += "(meta)data";
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break;
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default:
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R += "unknown";
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break;
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}
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return R;
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}//FLV::Tag::tagtype
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/// Returns the 32-bit timestamp of this tag.
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unsigned int FLV::Tag::tagTime(){
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return (data[4] << 16) + (data[5] << 8) + data[6] + (data[7] << 24);
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}//tagTime getter
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/// Sets the 32-bit timestamp of this tag.
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void FLV::Tag::tagTime(unsigned int T){
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data[4] = ((T >> 16) & 0xFF);
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data[5] = ((T >> 8) & 0xFF);
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data[6] = (T & 0xFF);
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data[7] = ((T >> 24) & 0xFF);
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}//tagTime setter
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/// Constructor for a new, empty, tag.
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/// The buffer length is initialized to 0, and later automatically
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/// increased if neccesary.
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FLV::Tag::Tag(){
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len = 0; buf = 0; data = 0; isKeyframe = false; done = true; sofar = 0;
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}//empty constructor
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/// Copy constructor, copies the contents of an existing tag.
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/// The buffer length is initialized to the actual size of the tag
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/// that is being copied, and later automaticallt increased if
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/// neccesary.
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FLV::Tag::Tag(const Tag& O){
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done = true;
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sofar = 0;
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buf = O.len;
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len = buf;
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if (len > 0){
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data = (char*)malloc(len);
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memcpy(data, O.data, len);
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}else{
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data = 0;
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}
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isKeyframe = O.isKeyframe;
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}//copy constructor
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/// Copy constructor from a RTMP chunk.
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/// Copies the contents of a RTMP chunk into a valid FLV tag.
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/// Exactly the same as making a chunk by through the default (empty) constructor
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/// and then calling FLV::Tag::ChunkLoader with the chunk as argument.
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FLV::Tag::Tag(const RTMPStream::Chunk& O){
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len = 0; buf = 0; data = 0; isKeyframe = false; done = true; sofar = 0;
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ChunkLoader(O);
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}
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/// Assignment operator - works exactly like the copy constructor.
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/// This operator checks for self-assignment.
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FLV::Tag & FLV::Tag::operator= (const FLV::Tag& O){
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if (this != &O){//no self-assignment
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len = O.len;
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if (len > 0){
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if (!data){
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data = (char*)malloc(len);
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buf = len;
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}else{
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if (buf < len){
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data = (char*)realloc(data, len);
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buf = len;
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}
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}
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memcpy(data, O.data, len);
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}
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isKeyframe = O.isKeyframe;
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}
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return *this;
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}//assignment operator
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/// FLV loader function from chunk.
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/// Copies the contents and wraps it in a FLV header.
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bool FLV::Tag::ChunkLoader(const RTMPStream::Chunk& O){
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len = O.len + 15;
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if (len > 0){
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if (!data){
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data = (char*)malloc(len);
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buf = len;
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}else{
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if (buf < len){
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data = (char*)realloc(data, len);
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buf = len;
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}
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}
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memcpy(data+11, &(O.data[0]), O.len);
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}
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((unsigned int *)(data+len-4))[0] = O.len;
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data[0] = O.msg_type_id;
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data[3] = O.len & 0xFF;
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data[2] = (O.len >> 8) & 0xFF;
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data[1] = (O.len >> 16) & 0xFF;
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tagTime(O.timestamp);
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return true;
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}
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/// Helper function for FLV::MemLoader.
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/// This function will try to read count bytes from data buffer D into buffer.
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/// This function should be called repeatedly until true.
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/// P and sofar are not the same value, because D may not start with the current tag.
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/// \param buffer The target buffer.
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/// \param count Amount of bytes to read.
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/// \param sofar Current amount read.
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/// \param D The location of the data buffer.
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/// \param S The size of the data buffer.
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/// \param P The current position in the data buffer. Will be updated to reflect new position.
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/// \return True if count bytes are read succesfully, false otherwise.
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bool FLV::Tag::MemReadUntil(char * buffer, unsigned int count, unsigned int & sofar, char * D, unsigned int S, unsigned int & P){
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if (sofar >= count){return true;}
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int r = 0;
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if (P+(count-sofar) > S){r = S-P;}else{r = count-sofar;}
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memcpy(buffer+sofar, D+P, r);
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P += r;
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sofar += r;
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if (sofar >= count){return true;}
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return false;
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}//Tag::MemReadUntil
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/// Try to load a tag from a data buffer in memory.
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/// This is a stateful function - if fed incorrect data, it will most likely never return true again!
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/// While this function returns false, the Tag might not contain valid data.
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/// \param D The location of the data buffer.
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/// \param S The size of the data buffer.
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/// \param P The current position in the data buffer. Will be updated to reflect new position.
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/// \return True if a whole tag is succesfully read, false otherwise.
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bool FLV::Tag::MemLoader(char * D, unsigned int S, unsigned int & P){
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if (buf < 15){data = (char*)realloc(data, 15); buf = 15;}
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if (done){
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//read a header
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if (MemReadUntil(data, 11, sofar, D, S, P)){
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//if its a correct FLV header, throw away and read tag header
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if (FLV::is_header(data)){
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if (MemReadUntil(data, 13, sofar, D, S, P)){
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if (FLV::check_header(data)){
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sofar = 0;
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memcpy(FLV::Header, data, 13);
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}else{FLV::Parse_Error = true; Error_Str = "Invalid header received."; return false;}
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}
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}else{
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//if a tag header, calculate length and read tag body
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len = data[3] + 15;
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len += (data[2] << 8);
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len += (data[1] << 16);
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if (buf < len){data = (char*)realloc(data, len); buf = len;}
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if (data[0] > 0x12){FLV::Parse_Error = true; Error_Str = "Invalid Tag received."; return false;}
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done = false;
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}
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}
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}else{
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//read tag body
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if (MemReadUntil(data, len, sofar, D, S, P)){
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//calculate keyframeness, next time read header again, return true
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if ((data[0] == 0x09) && (((data[11] & 0xf0) >> 4) == 1)){isKeyframe = true;}else{isKeyframe = false;}
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done = true;
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sofar = 0;
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return true;
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}
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}
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return false;
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}//Tag::MemLoader
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/// Helper function for FLV::SockLoader.
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/// This function will try to read count bytes from socket sock into buffer.
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/// This function should be called repeatedly until true.
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/// \param buffer The target buffer.
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/// \param count Amount of bytes to read.
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/// \param sofar Current amount read.
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/// \param sock Socket to read from.
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/// \return True if count bytes are read succesfully, false otherwise.
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bool FLV::Tag::SockReadUntil(char * buffer, unsigned int count, unsigned int & sofar, Socket::Connection & sock){
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if (sofar == count){return true;}
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if (!sock.read(buffer + sofar,count-sofar)){
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if (errno != EWOULDBLOCK){
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FLV::Parse_Error = true;
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Error_Str = "Error reading from socket.";
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}
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return false;
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}
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sofar += count-sofar;
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if (sofar == count){return true;}
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if (sofar > count){
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FLV::Parse_Error = true;
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Error_Str = "Socket buffer overflow.";
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}
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return false;
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}//Tag::SockReadUntil
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/// Try to load a tag from a socket.
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/// This is a stateful function - if fed incorrect data, it will most likely never return true again!
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/// While this function returns false, the Tag might not contain valid data.
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/// \param sock The socket to read from.
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/// \return True if a whole tag is succesfully read, false otherwise.
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bool FLV::Tag::SockLoader(Socket::Connection sock){
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if (buf < 15){data = (char*)realloc(data, 15); buf = 15;}
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if (done){
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if (SockReadUntil(data, 11, sofar, sock)){
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//if its a correct FLV header, throw away and read tag header
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if (FLV::is_header(data)){
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if (SockReadUntil(data, 13, sofar, sock)){
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if (FLV::check_header(data)){
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sofar = 0;
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memcpy(FLV::Header, data, 13);
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}else{FLV::Parse_Error = true; Error_Str = "Invalid header received."; return false;}
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}
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}else{
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//if a tag header, calculate length and read tag body
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len = data[3] + 15;
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len += (data[2] << 8);
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len += (data[1] << 16);
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if (buf < len){data = (char*)realloc(data, len); buf = len;}
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if (data[0] > 0x12){FLV::Parse_Error = true; Error_Str = "Invalid Tag received."; return false;}
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done = false;
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}
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}
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}else{
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//read tag body
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if (SockReadUntil(data, len, sofar, sock)){
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//calculate keyframeness, next time read header again, return true
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if ((data[0] == 0x09) && (((data[11] & 0xf0) >> 4) == 1)){isKeyframe = true;}else{isKeyframe = false;}
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done = true;
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sofar = 0;
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return true;
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}
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}
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return false;
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}//Tag::SockLoader
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/// Try to load a tag from a socket.
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/// This is a stateful function - if fed incorrect data, it will most likely never return true again!
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/// While this function returns false, the Tag might not contain valid data.
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/// \param sock The socket to read from.
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/// \return True if a whole tag is succesfully read, false otherwise.
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bool FLV::Tag::SockLoader(int sock){
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return SockLoader(Socket::Connection(sock));
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}//Tag::SockLoader
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/// Helper function for FLV::FileLoader.
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/// This function will try to read count bytes from file f into buffer.
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/// This function should be called repeatedly until true.
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/// \param buffer The target buffer.
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/// \param count Amount of bytes to read.
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/// \param sofar Current amount read.
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/// \param f File to read from.
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/// \return True if count bytes are read succesfully, false otherwise.
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bool FLV::Tag::FileReadUntil(char * buffer, unsigned int count, unsigned int & sofar, FILE * f){
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if (sofar >= count){return true;}
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int r = 0;
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r = fread(buffer + sofar,1,count-sofar,f);
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if (r < 0){FLV::Parse_Error = true; Error_Str = "File reading error."; return false;}
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sofar += r;
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if (sofar >= count){return true;}
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return false;
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}
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/// Try to load a tag from a file.
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/// This is a stateful function - if fed incorrect data, it will most likely never return true again!
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/// While this function returns false, the Tag might not contain valid data.
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/// \param f The file to read from.
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/// \return True if a whole tag is succesfully read, false otherwise.
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bool FLV::Tag::FileLoader(FILE * f){
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int preflags = fcntl(fileno(f), F_GETFL, 0);
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int postflags = preflags | O_NONBLOCK;
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fcntl(fileno(f), F_SETFL, postflags);
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if (buf < 15){data = (char*)realloc(data, 15); buf = 15;}
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if (done){
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//read a header
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if (FileReadUntil(data, 11, sofar, f)){
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//if its a correct FLV header, throw away and read tag header
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if (FLV::is_header(data)){
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if (FileReadUntil(data, 13, sofar, f)){
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if (FLV::check_header(data)){
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sofar = 0;
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memcpy(FLV::Header, data, 13);
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}else{FLV::Parse_Error = true; Error_Str = "Invalid header received."; return false;}
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}
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}else{
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//if a tag header, calculate length and read tag body
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len = data[3] + 15;
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len += (data[2] << 8);
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len += (data[1] << 16);
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if (buf < len){data = (char*)realloc(data, len); buf = len;}
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if (data[0] > 0x12){FLV::Parse_Error = true; Error_Str = "Invalid Tag received."; return false;}
|
|
done = false;
|
|
}
|
|
}
|
|
}else{
|
|
//read tag body
|
|
if (FileReadUntil(data, len, sofar, f)){
|
|
//calculate keyframeness, next time read header again, return true
|
|
if ((data[0] == 0x09) && (((data[11] & 0xf0) >> 4) == 1)){isKeyframe = true;}else{isKeyframe = false;}
|
|
done = true;
|
|
sofar = 0;
|
|
fcntl(fileno(f), F_SETFL, preflags);
|
|
return true;
|
|
}
|
|
}
|
|
fcntl(fileno(f), F_SETFL, preflags);
|
|
return false;
|
|
}//FLV_GetPacket
|