/* 从流媒体中读取多媒体packet。* Returns -3 if Play.Close/Stop, -2 if fatal error, -1 if no more media* packets, 0 if ignorable error, >0 if there is a media packet*/
static int
Read_1_Packet(RTMP *r, char *buf, unsigned int buflen)
{uint32_t prevTagSize = 0;int rtnGetNextMediaPacket = 0, ret = RTMP_READ_EOF;RTMPPacket packet = { 0 };int recopy = FALSE;unsigned int size;char *ptr, *pend;uint32_t nTimeStamp = 0;unsigned int len;//获取下一个packetrtnGetNextMediaPacket = RTMP_GetNextMediaPacket(r, &packet);while (rtnGetNextMediaPacket){char *packetBody = packet.m_body;unsigned int nPacketLen = packet.m_nBodySize;/* Return -3 if this was completed nicely with invoke message* Play.Stop or Play.Complete*/if (rtnGetNextMediaPacket == 2){RTMP_Log(RTMP_LOGDEBUG,"Got Play.Complete or Play.Stop from server. ""Assuming stream is complete");ret = RTMP_READ_COMPLETE;break;}//设置dataTyper->m_read.dataType |= (((packet.m_packetType == 0x08) << 2) |(packet.m_packetType == 0x09));//MessageID为9时，为视频数据，数据太小时。。。if (packet.m_packetType == 0x09 && nPacketLen <= 5){RTMP_Log(RTMP_LOGDEBUG, "ignoring too small video packet: size: %d",nPacketLen);ret = RTMP_READ_IGNORE;break;}//MessageID为8时，为音频数据，数据太小时。。。if (packet.m_packetType == 0x08 && nPacketLen <= 1){RTMP_Log(RTMP_LOGDEBUG, "ignoring too small audio packet: size: %d",nPacketLen);ret = RTMP_READ_IGNORE;break;}if (r->m_read.flags & RTMP_READ_SEEKING){ret = RTMP_READ_IGNORE;break;}
#ifdef _DEBUGRTMP_Log(RTMP_LOGDEBUG, "type: %02X, size: %d, TS: %d ms, abs TS: %d",packet.m_packetType, nPacketLen, packet.m_nTimeStamp,packet.m_hasAbsTimestamp);if (packet.m_packetType == 0x09)RTMP_Log(RTMP_LOGDEBUG, "frametype: %02X", (*packetBody & 0xf0));
#endifif (r->m_read.flags & RTMP_READ_RESUME){/* check the header if we get one *///此类packet的timestamp都是0if (packet.m_nTimeStamp == 0){//messageID=18，数据消息（AMF0）if (r->m_read.nMetaHeaderSize > 0&& packet.m_packetType == 0x12){//获取metadataAMFObject metaObj;int nRes =AMF_Decode(&metaObj, packetBody, nPacketLen, FALSE);if (nRes >= 0){AVal metastring;AMFProp_GetString(AMF_GetProp(&metaObj, NULL, 0),&metastring);if (AVMATCH(&metastring, &av_onMetaData)){/* compare */if ((r->m_read.nMetaHeaderSize != nPacketLen) ||(memcmp(r->m_read.metaHeader, packetBody,r->m_read.nMetaHeaderSize) != 0)){ret = RTMP_READ_ERROR;}}AMF_Reset(&metaObj);if (ret == RTMP_READ_ERROR)break;}}/* check first keyframe to make sure we got the right position* in the stream! (the first non ignored frame)*/if (r->m_read.nInitialFrameSize > 0){/* video or audio data */if (packet.m_packetType == r->m_read.initialFrameType&& r->m_read.nInitialFrameSize == nPacketLen){/* we don't compare the sizes since the packet can* contain several FLV packets, just make sure the* first frame is our keyframe (which we are going* to rewrite)*/if (memcmp(r->m_read.initialFrame, packetBody,r->m_read.nInitialFrameSize) == 0){RTMP_Log(RTMP_LOGDEBUG, "Checked keyframe successfully!");r->m_read.flags |= RTMP_READ_GOTKF;/* ignore it! (what about audio data after it? it is* handled by ignoring all 0ms frames, see below)*/ret = RTMP_READ_IGNORE;break;}}/* hande FLV streams, even though the server resends the* keyframe as an extra video packet it is also included* in the first FLV stream chunk and we have to compare* it and filter it out !!*///MessageID=22，聚合消息if (packet.m_packetType == 0x16){/* basically we have to find the keyframe with the* correct TS being nResumeTS*/unsigned int pos = 0;uint32_t ts = 0;while (pos + 11 < nPacketLen){/* size without header (11) and prevTagSize (4) */uint32_t dataSize =AMF_DecodeInt24(packetBody + pos + 1);ts = AMF_DecodeInt24(packetBody + pos + 4);ts |= (packetBody[pos + 7] << 24);#ifdef _DEBUGRTMP_Log(RTMP_LOGDEBUG,"keyframe search: FLV Packet: type %02X, dataSize: %d, timeStamp: %d ms",packetBody[pos], dataSize, ts);
#endif/* ok, is it a keyframe?:* well doesn't work for audio!*/if (packetBody[pos /*6928, test 0 */ ] ==r->m_read.initialFrameType/* && (packetBody[11]&0xf0) == 0x10 */ ){if (ts == r->m_read.nResumeTS){RTMP_Log(RTMP_LOGDEBUG,"Found keyframe with resume-keyframe timestamp!");if (r->m_read.nInitialFrameSize != dataSize|| memcmp(r->m_read.initialFrame,packetBody + pos + 11,r->m_read.nInitialFrameSize) != 0){RTMP_Log(RTMP_LOGERROR,"FLV Stream: Keyframe doesn't match!");ret = RTMP_READ_ERROR;break;}r->m_read.flags |= RTMP_READ_GOTFLVK;/* skip this packet?* check whether skippable:*/if (pos + 11 + dataSize + 4 > nPacketLen){RTMP_Log(RTMP_LOGWARNING,"Non skipable packet since it doesn't end with chunk, stream corrupt!");ret = RTMP_READ_ERROR;break;}packetBody += (pos + 11 + dataSize + 4);nPacketLen -= (pos + 11 + dataSize + 4);goto stopKeyframeSearch;}else if (r->m_read.nResumeTS < ts){/* the timestamp ts will only increase with* further packets, wait for seek*/goto stopKeyframeSearch;}}pos += (11 + dataSize + 4);}if (ts < r->m_read.nResumeTS){RTMP_Log(RTMP_LOGERROR,"First packet does not contain keyframe, all ""timestamps are smaller than the keyframe ""timestamp; probably the resume seek failed?");}stopKeyframeSearch:;if (!(r->m_read.flags & RTMP_READ_GOTFLVK)){RTMP_Log(RTMP_LOGERROR,"Couldn't find the seeked keyframe in this chunk!");ret = RTMP_READ_IGNORE;break;}}}}if (packet.m_nTimeStamp > 0&& (r->m_read.flags & (RTMP_READ_GOTKF|RTMP_READ_GOTFLVK))){/* another problem is that the server can actually change from* 09/08 video/audio packets to an FLV stream or vice versa and* our keyframe check will prevent us from going along with the* new stream if we resumed.** in this case set the 'found keyframe' variables to true.* We assume that if we found one keyframe somewhere and were* already beyond TS > 0 we have written data to the output* which means we can accept all forthcoming data including the* change between 08/09 <-> FLV packets*/r->m_read.flags |= (RTMP_READ_GOTKF|RTMP_READ_GOTFLVK);}/* skip till we find our keyframe* (seeking might put us somewhere before it)*/if (!(r->m_read.flags & RTMP_READ_GOTKF) &&packet.m_packetType != 0x16){RTMP_Log(RTMP_LOGWARNING,"Stream does not start with requested frame, ignoring data... ");r->m_read.nIgnoredFrameCounter++;if (r->m_read.nIgnoredFrameCounter > MAX_IGNORED_FRAMES)ret = RTMP_READ_ERROR; /* fatal error, couldn't continue stream */elseret = RTMP_READ_IGNORE;break;}/* ok, do the same for FLV streams */if (!(r->m_read.flags & RTMP_READ_GOTFLVK) &&packet.m_packetType == 0x16){RTMP_Log(RTMP_LOGWARNING,"Stream does not start with requested FLV frame, ignoring data... ");r->m_read.nIgnoredFlvFrameCounter++;if (r->m_read.nIgnoredFlvFrameCounter > MAX_IGNORED_FRAMES)ret = RTMP_READ_ERROR;elseret = RTMP_READ_IGNORE;break;}/* we have to ignore the 0ms frames since these are the first* keyframes; we've got these so don't mess around with multiple* copies sent by the server to us! (if the keyframe is found at a* later position there is only one copy and it will be ignored by* the preceding if clause)*/if (!(r->m_read.flags & RTMP_READ_NO_IGNORE) &&packet.m_packetType != 0x16){ /* exclude type 0x16 (FLV) since it can* contain several FLV packets */if (packet.m_nTimeStamp == 0){ret = RTMP_READ_IGNORE;break;}else{/* stop ignoring packets */r->m_read.flags |= RTMP_READ_NO_IGNORE;}}}/* calculate packet size and allocate slop buffer if necessary */size = nPacketLen +((packet.m_packetType == 0x08 || packet.m_packetType == 0x09|| packet.m_packetType == 0x12) ? 11 : 0) +(packet.m_packetType != 0x16 ? 4 : 0);if (size + 4 > buflen){/* the extra 4 is for the case of an FLV stream without a last* prevTagSize (we need extra 4 bytes to append it) */r->m_read.buf = (char *) malloc(size + 4);if (r->m_read.buf == 0){RTMP_Log(RTMP_LOGERROR, "Couldn't allocate memory!");ret = RTMP_READ_ERROR; /* fatal error */break;}recopy = TRUE;ptr = r->m_read.buf;}else{ptr = buf;}pend = ptr + size + 4;/* use to return timestamp of last processed packet *//* audio (0x08), video (0x09) or metadata (0x12) packets :* construct 11 byte header then add rtmp packet's data */if (packet.m_packetType == 0x08 || packet.m_packetType == 0x09|| packet.m_packetType == 0x12){nTimeStamp = r->m_read.nResumeTS + packet.m_nTimeStamp;prevTagSize = 11 + nPacketLen;*ptr = packet.m_packetType;ptr++;ptr = AMF_EncodeInt24(ptr, pend, nPacketLen);#if 0if(packet.m_packetType == 0x09) { /* video *//* H264 fix: */if((packetBody[0] & 0x0f) == 7) { /* CodecId = H264 */uint8_t packetType = *(packetBody+1);uint32_t ts = AMF_DecodeInt24(packetBody+2); /* composition time */int32_t cts = (ts+0xff800000)^0xff800000;RTMP_Log(RTMP_LOGDEBUG, "cts : %d\n", cts);nTimeStamp -= cts;/* get rid of the composition time */CRTMP::EncodeInt24(packetBody+2, 0);}RTMP_Log(RTMP_LOGDEBUG, "VIDEO: nTimeStamp: 0x%08X (%d)\n", nTimeStamp, nTimeStamp);}
#endifptr = AMF_EncodeInt24(ptr, pend, nTimeStamp);*ptr = (char)((nTimeStamp & 0xFF000000) >> 24);ptr++;/* stream id */ptr = AMF_EncodeInt24(ptr, pend, 0);}memcpy(ptr, packetBody, nPacketLen);len = nPacketLen;/* correct tagSize and obtain timestamp if we have an FLV stream */if (packet.m_packetType == 0x16){unsigned int pos = 0;int delta;/* grab first timestamp and see if it needs fixing */
// nTimeStamp = AMF_DecodeInt24(packetBody + 4);// nTimeStamp |= (packetBody[7] << 24);
// delta = packet.m_nTimeStamp - nTimeStamp;while (pos + 11 < nPacketLen){/* size without header (11) and without prevTagSize (4) */uint32_t dataSize = AMF_DecodeInt24(packetBody + pos + 1);nTimeStamp = AMF_DecodeInt24(packetBody + pos + 4);nTimeStamp |= (packetBody[pos + 7] << 24);// if (delta)
// {
// nTimeStamp += delta;
// AMF_EncodeInt24(ptr+pos+4, pend, nTimeStamp);
// ptr[pos+7] = nTimeStamp>>24;
// }/* set data type */r->m_read.dataType |= (((*(packetBody + pos) == 0x08) << 2) |(*(packetBody + pos) == 0x09));if (pos + 11 + dataSize + 4 > nPacketLen){if (pos + 11 + dataSize > nPacketLen){RTMP_Log(RTMP_LOGERROR,"Wrong data size (%lu), stream corrupted, aborting!",dataSize);ret = RTMP_READ_ERROR;break;}RTMP_Log(RTMP_LOGWARNING, "No tagSize found, appending!");/* we have to append a last tagSize! */prevTagSize = dataSize + 11;AMF_EncodeInt32(ptr + pos + 11 + dataSize, pend,prevTagSize);size += 4;len += 4;}else{prevTagSize =AMF_DecodeInt32(packetBody + pos + 11 + dataSize);#ifdef _DEBUGRTMP_Log(RTMP_LOGDEBUG,"FLV Packet: type %02X, dataSize: %lu, tagSize: %lu, timeStamp: %lu ms",(unsigned char)packetBody[pos], dataSize, prevTagSize,nTimeStamp);
#endifif (prevTagSize != (dataSize + 11)){
#ifdef _DEBUGRTMP_Log(RTMP_LOGWARNING,"Tag and data size are not consitent, writing tag size according to dataSize+11: %d",dataSize + 11);
#endifprevTagSize = dataSize + 11;AMF_EncodeInt32(ptr + pos + 11 + dataSize, pend,prevTagSize);}}pos += prevTagSize + 4; /*(11+dataSize+4); */}}ptr += len;if (packet.m_packetType != 0x16){/* FLV tag packets contain their own prevTagSize */AMF_EncodeInt32(ptr, pend, prevTagSize);}/* In non-live this nTimeStamp can contain an absolute TS.* Update ext timestamp with this absolute offset in non-live mode* otherwise report the relative one*//* RTMP_Log(RTMP_LOGDEBUG, "type: %02X, size: %d, pktTS: %dms, TS: %dms, bLiveStream: %d", packet.m_packetType, nPacketLen, packet.m_nTimeStamp, nTimeStamp, r->Link.lFlags & RTMP_LF_LIVE); */r->m_read.timestamp = (r->Link.lFlags & RTMP_LF_LIVE) ? packet.m_nTimeStamp : nTimeStamp;ret = size;break;}if (rtnGetNextMediaPacket)RTMPPacket_Free(&packet);if (recopy){len = ret > buflen ? buflen : ret;memcpy(buf, r->m_read.buf, len);r->m_read.bufpos = r->m_read.buf + len;r->m_read.buflen = ret - len;}return ret;
}
