rtphint.cpp

AAC编解码源码

/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is MPEG4IP.
 * 
 * The Initial Developer of the Original Code is Cisco Systems Inc.
 * Portions created by Cisco Systems Inc. are
 * Copyright (C) Cisco Systems Inc. 2001.  All Rights Reserved.
 * 
 * Contributor(s): 
 *		Dave Mackie		[e-mail]
 */

#include "mp4common.h"

/* rtp hint track operations */

MP4RtpHintTrack::MP4RtpHintTrack(MP4File* pFile, MP4Atom* pTrakAtom)
	: MP4Track(pFile, pTrakAtom)
{
	m_pRefTrack = NULL;

	m_pRtpMapProperty = NULL;
	m_pPayloadNumberProperty = NULL;
	m_pMaxPacketSizeProperty = NULL;
	m_pSnroProperty = NULL;
	m_pTsroProperty = NULL;

	m_pReadHint = NULL;
	m_pReadHintSample = NULL;
	m_readHintSampleSize = 0;

	m_pWriteHint = NULL;
	m_writeHintId = MP4_INVALID_SAMPLE_ID;
	m_writePacketId = 0;

	m_pTrpy = NULL;
	m_pNump = NULL;
	m_pTpyl = NULL;
	m_pMaxr = NULL;
	m_pDmed = NULL;
	m_pDimm = NULL;
	m_pPmax = NULL;
	m_pDmax = NULL;

	m_pMaxPdu = NULL;
	m_pAvgPdu = NULL;
	m_pMaxBitRate = NULL;
	m_pAvgBitRate = NULL;

	m_thisSec = 0;
	m_bytesThisSec = 0;
	m_bytesThisHint = 0;
	m_bytesThisPacket = 0;
}

MP4RtpHintTrack::~MP4RtpHintTrack()
{
	delete m_pReadHint;
	delete m_pReadHintSample;
	delete m_pWriteHint;
}

void MP4RtpHintTrack::InitRefTrack()
{
	if (m_pRefTrack == NULL) {
		MP4Integer32Property* pRefTrackIdProperty = NULL;
		m_pTrakAtom->FindProperty(
			"trak.tref.hint.entries[0].trackId",
			(MP4Property**)&pRefTrackIdProperty);
		ASSERT(pRefTrackIdProperty);

		m_pRefTrack = m_pFile->GetTrack(pRefTrackIdProperty->GetValue());
	}
}

void MP4RtpHintTrack::InitRtpStart() 
{
	struct timeval tv;
	gettimeofday(&tv, NULL);
	srandom((tv.tv_usec << 12) | (tv.tv_sec & 0xFFF));

	ASSERT(m_pTrakAtom);

	m_pTrakAtom->FindProperty(
		"trak.udta.hnti.rtp .snro.offset",
		(MP4Property**)&m_pSnroProperty);

	if (m_pSnroProperty) {
		m_rtpSequenceStart = m_pSnroProperty->GetValue();
	} else {
		m_rtpSequenceStart = random();
	}

	m_pTrakAtom->FindProperty(
		"trak.udta.hnti.rtp .tsro.offset",
		(MP4Property**)&m_pTsroProperty);

	if (m_pTsroProperty) {
		m_rtpTimestampStart = m_pTsroProperty->GetValue();
	} else {
		m_rtpTimestampStart = random();
	}
}

void MP4RtpHintTrack::ReadHint(
	MP4SampleId hintSampleId,
	u_int16_t* pNumPackets)
{
	if (m_pRefTrack == NULL) {
		InitRefTrack();
		InitRtpStart();
	}

	// dispose of any old hint
	delete m_pReadHint;
	m_pReadHint = NULL;
	delete m_pReadHintSample;
	m_pReadHintSample = NULL;
	m_readHintSampleSize = 0;

	// read the desired hint sample into memory
	ReadSample(
		hintSampleId, 
		&m_pReadHintSample, 
		&m_readHintSampleSize,
		&m_readHintTimestamp);

	m_pFile->EnableMemoryBuffer(m_pReadHintSample, m_readHintSampleSize);

	m_pReadHint = new MP4RtpHint(this);
	m_pReadHint->Read(m_pFile);

	m_pFile->DisableMemoryBuffer();

	if (pNumPackets) {
		*pNumPackets = GetHintNumberOfPackets();
	}
}

u_int16_t MP4RtpHintTrack::GetHintNumberOfPackets()
{
	if (m_pReadHint == NULL) {
		throw new MP4Error("no hint has been read",
			"MP4GetRtpHintNumberOfPackets");
	}
	return m_pReadHint->GetNumberOfPackets();
}

bool MP4RtpHintTrack::GetPacketBFrame(u_int16_t packetIndex)
{
	if (m_pReadHint == NULL) {
		throw new MP4Error("no hint has been read",
			"MP4GetRtpPacketBFrame");
	}
	MP4RtpPacket* pPacket =
		m_pReadHint->GetPacket(packetIndex);

	return pPacket->IsBFrame();
}

u_int16_t MP4RtpHintTrack::GetPacketTransmitOffset(u_int16_t packetIndex)
{
	if (m_pReadHint == NULL) {
		throw new MP4Error("no hint has been read",
			"MP4GetRtpPacketTransmitOffset");
	}

	MP4RtpPacket* pPacket =
		m_pReadHint->GetPacket(packetIndex);

	return pPacket->GetTransmitOffset();
}

void MP4RtpHintTrack::ReadPacket(
	u_int16_t packetIndex,
	u_int8_t** ppBytes, 
	u_int32_t* pNumBytes,
	u_int32_t ssrc,
	bool addHeader,
	bool addPayload)
{
	if (m_pReadHint == NULL) {
		throw new MP4Error("no hint has been read",
			"MP4ReadRtpPacket");
	}
	if (!addHeader && !addPayload) {
		throw new MP4Error("no data requested",
			"MP4ReadRtpPacket");
	}

	MP4RtpPacket* pPacket =
		m_pReadHint->GetPacket(packetIndex);

	*pNumBytes = 0;
	if (addHeader) {
		*pNumBytes += 12;
	}
	if (addPayload) {
		*pNumBytes += pPacket->GetDataSize();
	}

	// if needed, allocate the packet memory
	bool buffer_malloc = false;

	if (*ppBytes == NULL) {
		*ppBytes = (u_int8_t*)MP4Malloc(*pNumBytes);
		buffer_malloc = true;
	}

	try {
		u_int8_t* pDest = *ppBytes;

		if (addHeader) {
			*pDest++ =
				0x80 | (pPacket->GetPBit() << 5) | (pPacket->GetXBit() << 4);

			*pDest++ =
				(pPacket->GetMBit() << 7) | pPacket->GetPayload();

			*((u_int16_t*)pDest) = 
				htons(m_rtpSequenceStart + pPacket->GetSequenceNumber());
			pDest += 2; 

			*((u_int32_t*)pDest) = 
				htonl(m_rtpTimestampStart + (u_int32_t)m_readHintTimestamp);
			pDest += 4; 

			*((u_int32_t*)pDest) = 
				htonl(ssrc);
			pDest += 4;
		}

		if (addPayload) {
			pPacket->GetData(pDest);
		}
	}
	catch (MP4Error* e) {
		if (buffer_malloc) {
			MP4Free(*ppBytes);
			*ppBytes = NULL;
		}
		throw e;
	}

	VERBOSE_READ_HINT(m_pFile->GetVerbosity(),
		printf("ReadPacket: %u ", packetIndex);
		MP4HexDump(*ppBytes, *pNumBytes););
}

MP4Timestamp MP4RtpHintTrack::GetRtpTimestampStart()
{
	if (m_pRefTrack == NULL) {
		InitRefTrack();
		InitRtpStart();
	}

	return m_rtpTimestampStart;
}

void MP4RtpHintTrack::SetRtpTimestampStart(MP4Timestamp start)
{
	if (!m_pTsroProperty) {
		MP4Atom* pTsroAtom =
			m_pFile->AddDescendantAtoms(m_pTrakAtom, "udta.hnti.rtp .tsro");

		ASSERT(pTsroAtom);

		pTsroAtom->FindProperty("offset",
			(MP4Property**)&m_pTsroProperty);

		ASSERT(m_pTsroProperty);
	}

	m_pTsroProperty->SetValue(start);
	m_rtpTimestampStart = start;
}

void MP4RtpHintTrack::InitPayload()
{
	ASSERT(m_pTrakAtom);

	if (m_pRtpMapProperty == NULL) {
		m_pTrakAtom->FindProperty(
			"trak.udta.hinf.payt.rtpMap",
			(MP4Property**)&m_pRtpMapProperty);
	}

	if (m_pPayloadNumberProperty == NULL) {
		m_pTrakAtom->FindProperty(
			"trak.udta.hinf.payt.payloadNumber",
			(MP4Property**)&m_pPayloadNumberProperty);
	}

	if (m_pMaxPacketSizeProperty == NULL) {
		m_pTrakAtom->FindProperty(
			"trak.mdia.minf.stbl.stsd.rtp .maxPacketSize",
			(MP4Property**)&m_pMaxPacketSizeProperty);
	}
}

void MP4RtpHintTrack::GetPayload(
	char** ppPayloadName,
	u_int8_t* pPayloadNumber,
	u_int16_t* pMaxPayloadSize,
	char **ppEncodingParams)
{
	InitPayload();

	if (ppPayloadName || ppEncodingParams) {
	  if (ppPayloadName) 
	    *ppPayloadName = NULL;
	  if (ppEncodingParams)
	    *ppEncodingParams = NULL;
		if (m_pRtpMapProperty) {
			const char* pRtpMap = m_pRtpMapProperty->GetValue();
			char* pSlash = strchr(pRtpMap, '/');

			u_int32_t length;
			if (pSlash) {
				length = pSlash - pRtpMap;
			} else {
				length = strlen(pRtpMap);
			}

			if (ppPayloadName) {
			  *ppPayloadName = (char*)MP4Calloc(length + 1);
			  strncpy(*ppPayloadName, pRtpMap, length); 
			}
			if (pSlash && ppEncodingParams) {
			  pSlash = strchr(pSlash, '/');
			  if (pSlash != NULL) {
			    pSlash++;
			    if (pSlash != '\0') {
			      length = strlen(pRtpMap) - (pSlash - pRtpMap);
			      *ppEncodingParams = (char *)MP4Calloc(length + 1);
			      strncpy(*ppEncodingParams, pSlash, length);
			    }
			  }
			}
		} 
	}

	if (pPayloadNumber) {
		if (m_pPayloadNumberProperty) {
			*pPayloadNumber = m_pPayloadNumberProperty->GetValue();
		} else {
			*pPayloadNumber = 0;
		}
	}

	if (pMaxPayloadSize) {
		if (m_pMaxPacketSizeProperty) {
			*pMaxPayloadSize = m_pMaxPacketSizeProperty->GetValue();
		} else {
			*pMaxPayloadSize = 0;
		}
	}
}

void MP4RtpHintTrack::SetPayload(
	const char* payloadName,
	u_int8_t payloadNumber,
	u_int16_t maxPayloadSize, 
	const char *encoding_parms,
	bool include_rtp_map,
	bool include_mpeg4_esid)
{
	InitRefTrack();
	InitPayload();

	ASSERT(m_pRtpMapProperty);
	ASSERT(m_pPayloadNumberProperty);
	ASSERT(m_pMaxPacketSizeProperty);
	
	size_t len = strlen(payloadName) + 16;
	if (encoding_parms != NULL) {
	  size_t temp = strlen(encoding_parms);
	  if (temp == 0) {
	    encoding_parms = NULL;
	  } else {
	    len += temp;
	  }
	}

	char* rtpMapBuf = (char*)MP4Malloc(len);
	sprintf(rtpMapBuf, "%s/%u%c%s", 
		payloadName, 
		GetTimeScale(),
		encoding_parms != NULL ? '/' : '\0',
		encoding_parms == NULL ? "" : encoding_parms);
	m_pRtpMapProperty->SetValue(rtpMapBuf);
	
	m_pPayloadNumberProperty->SetValue(payloadNumber);

	if (maxPayloadSize == 0) {
		maxPayloadSize = 1460;
	} 
	m_pMaxPacketSizeProperty->SetValue(maxPayloadSize);

	// set sdp media type
	const char* sdpMediaType;
	if (!strcmp(m_pRefTrack->GetType(), MP4_AUDIO_TRACK_TYPE)) {
		sdpMediaType = "audio";
	} else if (!strcmp(m_pRefTrack->GetType(), MP4_VIDEO_TRACK_TYPE)) {
		sdpMediaType = "video";
	} else {
		sdpMediaType = "application";
	}

	char* sdpBuf = (char*)MP4Malloc(
		strlen(sdpMediaType) + strlen(rtpMapBuf) + 256);
	uint32_t buflen;
	buflen = sprintf(sdpBuf, 
			 "m=%s 0 RTP/AVP %u\015\012"
			 "a=control:trackID=%u\015\012",
			 sdpMediaType, payloadNumber,
			 m_trackId);
	if (include_rtp_map) {
	  buflen += sprintf(sdpBuf + buflen, 
			    "a=rtpmap:%u %s\015\012",
			    payloadNumber, rtpMapBuf);
	}
	if (include_mpeg4_esid) {
	  sprintf(sdpBuf + buflen, 
		  "a=mpeg4-esid:%u\015\012",
		  m_pRefTrack->GetId());
	}

	MP4StringProperty* pSdpProperty = NULL;
	m_pTrakAtom->FindProperty("trak.udta.hnti.sdp .sdpText",
		(MP4Property**)&pSdpProperty);
	ASSERT(pSdpProperty);
	pSdpProperty->SetValue(sdpBuf);

	// cleanup
	MP4Free(rtpMapBuf);
	MP4Free(sdpBuf);
}

void MP4RtpHintTrack::AddHint(bool isBFrame, u_int32_t timestampOffset)
{
	// on first hint, need to lookup the reference track
	if (m_writeHintId == MP4_INVALID_SAMPLE_ID) {
		InitRefTrack();