ref: 9e7e4c1abd383bd519551222d3e553c32729b035
dir: /common/mp4av/rfc3119.cpp/
/*
* 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. 2000-2002. All Rights Reserved.
*
* Contributor(s):
* Dave Mackie dmackie@cisco.com
*/
/*
* Notes:
* - file formatted with tabstops == 4 spaces
*/
#include <mp4av_common.h>
// LATER get these on the stack so library is thread-safe!
// file globals
static bool doInterleave;
static u_int32_t samplesPerPacket;
static u_int32_t samplesPerGroup;
static MP4AV_Mp3Header* pFrameHeaders = NULL;
static u_int16_t* pAduOffsets = NULL;
static bool GetFrameInfo(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4AV_Mp3Header** ppFrameHeaders,
u_int16_t** ppAduOffsets)
{
// allocate memory to hold the frame info that we need
u_int32_t numSamples =
MP4GetTrackNumberOfSamples(mp4File, mediaTrackId);
*ppFrameHeaders =
(MP4AV_Mp3Header*)calloc((numSamples + 2), sizeof(u_int32_t));
if (*ppFrameHeaders == NULL) {
return false;
}
*ppAduOffsets =
(u_int16_t*)calloc((numSamples + 2), sizeof(u_int16_t));
if (*ppAduOffsets == NULL) {
free(*ppFrameHeaders);
return false;
}
// for each sample
for (MP4SampleId sampleId = 1; sampleId <= numSamples; sampleId++) {
u_int8_t* pSample = NULL;
u_int32_t sampleSize = 0;
// read it
MP4ReadSample(
mp4File,
mediaTrackId,
sampleId,
&pSample,
&sampleSize);
// extract the MP3 frame header
MP4AV_Mp3Header mp3hdr =
MP4AV_Mp3HeaderFromBytes(pSample);
// store what we need
(*ppFrameHeaders)[sampleId] = mp3hdr;
(*ppAduOffsets)[sampleId] =
MP4AV_Mp3GetAduOffset(pSample, sampleSize);
free(pSample);
}
return true;
}
static u_int16_t GetFrameHeaderSize(MP4SampleId sampleId)
{
return 4 + MP4AV_Mp3GetCrcSize(pFrameHeaders[sampleId])
+ MP4AV_Mp3GetSideInfoSize(pFrameHeaders[sampleId]);
}
static u_int16_t GetFrameDataSize(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4SampleId sampleId)
{
return MP4GetSampleSize(mp4File, mediaTrackId, sampleId)
- GetFrameHeaderSize(sampleId);
}
u_int32_t MP4AV_Rfc3119GetAduSize(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4SampleId sampleId)
{
u_int32_t sampleSize = MP4GetSampleSize(mp4File, mediaTrackId, sampleId);
return pAduOffsets[sampleId] + sampleSize - pAduOffsets[sampleId + 1];
}
static u_int16_t GetMaxAduSize(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId)
{
u_int32_t numSamples =
MP4GetTrackNumberOfSamples(mp4File, mediaTrackId);
u_int16_t maxAduSize = 0;
for (MP4SampleId sampleId = 1; sampleId <= numSamples; sampleId++) {
u_int16_t aduSize =
MP4AV_Rfc3119GetAduSize(mp4File, mediaTrackId, sampleId);
if (aduSize > maxAduSize) {
maxAduSize = aduSize;
}
}
return maxAduSize;
}
static u_int16_t GetAduDataSize(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4SampleId sampleId)
{
return MP4AV_Rfc3119GetAduSize(mp4File, mediaTrackId, sampleId)
- GetFrameHeaderSize(sampleId);
}
static void AddFrameHeader(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4TrackId hintTrackId,
MP4SampleId sampleId)
{
// when interleaving we replace the 11 bit mp3 frame sync
if (doInterleave) {
// compute interleave index and interleave cycle from sampleId
u_int8_t interleaveIndex =
(sampleId - 1) % samplesPerGroup;
u_int8_t interleaveCycle =
((sampleId - 1) / samplesPerGroup) & 0x7;
u_int8_t interleaveHeader[4];
interleaveHeader[0] =
interleaveIndex;
interleaveHeader[1] =
(interleaveCycle << 5) | ((pFrameHeaders[sampleId] >> 16) & 0x1F);
interleaveHeader[2] =
(pFrameHeaders[sampleId] >> 8) & 0xFF;
interleaveHeader[3] =
pFrameHeaders[sampleId] & 0xFF;
MP4AddRtpImmediateData(mp4File, hintTrackId,
interleaveHeader, 4);
// add crc and side info from current mp3 frame
MP4AddRtpSampleData(mp4File, hintTrackId,
sampleId, 4, GetFrameHeaderSize(sampleId) - 4);
} else {
// add mp3 header, crc, and side info from current mp3 frame
MP4AddRtpSampleData(mp4File, hintTrackId,
sampleId, 0, GetFrameHeaderSize(sampleId));
}
}
static void CollectAduDataBlocks(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4TrackId hintTrackId,
MP4SampleId sampleId,
u_int8_t* pNumBlocks,
u_int32_t** ppOffsets,
u_int32_t** ppSizes)
{
// go back from sampleId until
// accumulated data bytes can fill sample's ADU
MP4SampleId sid = sampleId;
u_int8_t numBlocks = 1;
u_int32_t prevDataBytes = 0;
const u_int8_t maxBlocks = 8;
*ppOffsets = new u_int32_t[maxBlocks];
*ppSizes = new u_int32_t[maxBlocks];
(*ppOffsets)[0] = GetFrameHeaderSize(sampleId);
(*ppSizes)[0] = GetFrameDataSize(mp4File, mediaTrackId, sid);
while (true) {
if (prevDataBytes >= pAduOffsets[sampleId]) {
u_int32_t adjust =
prevDataBytes - pAduOffsets[sampleId];
(*ppOffsets)[numBlocks-1] += adjust;
(*ppSizes)[numBlocks-1] -= adjust;
break;
}
sid--;
numBlocks++;
if (sid == 0 || numBlocks > maxBlocks) {
throw EIO; // media bitstream error
}
(*ppOffsets)[numBlocks-1] = GetFrameHeaderSize(sid);
(*ppSizes)[numBlocks-1] = GetFrameDataSize(mp4File, mediaTrackId, sid);
prevDataBytes += (*ppSizes)[numBlocks-1];
}
*pNumBlocks = numBlocks;
}
bool MP4AV_Rfc3119Concatenator(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4TrackId hintTrackId,
u_int8_t samplesThisHint,
MP4SampleId* pSampleIds,
MP4Duration hintDuration,
u_int16_t maxPayloadSize)
{
// handle degenerate case
if (samplesThisHint == 0) {
return true;
}
// construct the new hint
MP4AddRtpHint(mp4File, hintTrackId);
MP4AddRtpPacket(mp4File, hintTrackId, false);
// rfc 3119 per adu payload header
u_int8_t payloadHeader[2];
// for each given sample
for (u_int8_t i = 0; i < samplesThisHint; i++) {
MP4SampleId sampleId = pSampleIds[i];
u_int16_t aduSize =
MP4AV_Rfc3119GetAduSize(mp4File, mediaTrackId, sampleId);
// add the per ADU payload header
payloadHeader[0] = 0x40 | ((aduSize >> 8) & 0x3F);
payloadHeader[1] = aduSize & 0xFF;
MP4AddRtpImmediateData(mp4File, hintTrackId,
(u_int8_t*)&payloadHeader, sizeof(payloadHeader));
// add the mp3 frame header and side info
AddFrameHeader(mp4File, mediaTrackId, hintTrackId, sampleId);
// collect the info on the adu main data fragments
u_int8_t numDataBlocks;
u_int32_t* pDataOffsets;
u_int32_t* pDataSizes;
CollectAduDataBlocks(mp4File, mediaTrackId, hintTrackId, sampleId,
&numDataBlocks, &pDataOffsets, &pDataSizes);
// collect the needed blocks of data
u_int16_t dataSize = 0;
u_int16_t aduDataSize =
GetAduDataSize(mp4File, mediaTrackId, sampleId);
for (int8_t i = numDataBlocks - 1;
i >= 0 && dataSize < aduDataSize; i--) {
u_int32_t blockSize = pDataSizes[i];
if ((u_int32_t)(aduDataSize - dataSize) < blockSize) {
blockSize = (u_int32_t)(aduDataSize - dataSize);
}
MP4AddRtpSampleData(mp4File, hintTrackId,
sampleId - i, pDataOffsets[i], blockSize);
dataSize += blockSize;
}
delete [] pDataOffsets;
delete [] pDataSizes;
}
// write the hint
MP4WriteRtpHint(mp4File, hintTrackId, hintDuration);
return true;
}
bool MP4AV_Rfc3119Fragmenter(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
MP4TrackId hintTrackId,
MP4SampleId sampleId,
u_int32_t aduSize,
MP4Duration sampleDuration,
u_int16_t maxPayloadSize)
{
MP4AddRtpHint(mp4File, hintTrackId);
MP4AddRtpPacket(mp4File, hintTrackId, false);
// rfc 3119 payload header
u_int8_t payloadHeader[2];
u_int16_t payloadSize =
sizeof(payloadHeader) + GetFrameHeaderSize(sampleId);
// guard against ridiculous payload sizes
if (payloadSize > maxPayloadSize) {
return false;
}
// add the per ADU fragment payload header
payloadHeader[0] = 0x40 | ((aduSize >> 8) & 0x3F);
payloadHeader[1] = aduSize & 0xFF;
MP4AddRtpImmediateData(mp4File, hintTrackId,
(u_int8_t*)&payloadHeader, sizeof(payloadHeader));
payloadHeader[0] |= 0x80; // mark future packets as continuations
// add the mp3 frame header and side info
AddFrameHeader(mp4File, mediaTrackId, hintTrackId, sampleId);
// collect the info on the adu main data fragments
u_int8_t numDataBlocks;
u_int32_t* pDataOffsets;
u_int32_t* pDataSizes;
CollectAduDataBlocks(mp4File, mediaTrackId, hintTrackId, sampleId,
&numDataBlocks, &pDataOffsets, &pDataSizes);
u_int16_t dataSize = 0;
u_int16_t aduDataSize =
GetAduDataSize(mp4File, mediaTrackId, sampleId);
// for each data block
for (int8_t i = numDataBlocks - 1; i >= 0 && dataSize < aduDataSize; i--) {
u_int32_t blockSize = pDataSizes[i];
u_int32_t blockOffset = pDataOffsets[i];
// we may not need all of a block
if ((u_int32_t)(aduDataSize - dataSize) < blockSize) {
blockSize = (u_int32_t)(aduDataSize - dataSize);
}
dataSize += blockSize;
// while data left in this block
while (blockSize > 0) {
u_int16_t payloadRemaining = maxPayloadSize - payloadSize;
if (blockSize < payloadRemaining) {
// the entire block fits in this packet
MP4AddRtpSampleData(mp4File, hintTrackId,
sampleId - i, blockOffset, blockSize);
payloadSize += blockSize;
blockSize = 0;
} else {
// the block fills this packet
MP4AddRtpSampleData(mp4File, hintTrackId,
sampleId - i, blockOffset, payloadRemaining);
blockOffset += payloadRemaining;
blockSize -= payloadRemaining;
// start a new RTP packet
MP4AddRtpPacket(mp4File, hintTrackId, false);
// add the fragment payload header
MP4AddRtpImmediateData(mp4File, hintTrackId,
(u_int8_t*)&payloadHeader, sizeof(payloadHeader));
payloadSize = sizeof(payloadHeader);
}
}
}
// write the hint
MP4WriteRtpHint(mp4File, hintTrackId, sampleDuration);
// cleanup
delete [] pDataOffsets;
delete [] pDataSizes;
return true;
}
extern "C" bool MP4AV_Rfc3119Hinter(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
bool interleave,
u_int16_t maxPayloadSize)
{
int rc;
u_int32_t numSamples =
MP4GetTrackNumberOfSamples(mp4File, mediaTrackId);
if (numSamples == 0) {
return false;
}
u_int8_t audioType =
MP4GetTrackEsdsObjectTypeId(mp4File, mediaTrackId);
if (!MP4_IS_MP3_AUDIO_TYPE(audioType)) {
return false;
}
MP4Duration sampleDuration =
MP4AV_GetAudioSampleDuration(mp4File, mediaTrackId);
if (sampleDuration == MP4_INVALID_DURATION) {
return false;
}
// choose 500 ms max latency
MP4Duration maxLatency =
MP4GetTrackTimeScale(mp4File, mediaTrackId) / 2;
if (maxLatency == 0) {
return false;
}
MP4TrackId hintTrackId =
MP4AddHintTrack(mp4File, mediaTrackId);
if (hintTrackId == MP4_INVALID_TRACK_ID) {
return false;
}
doInterleave = interleave;
u_int8_t payloadNumber = MP4_SET_DYNAMIC_PAYLOAD;
MP4SetHintTrackRtpPayload(mp4File, hintTrackId,
"mpa-robust", &payloadNumber, 0);
// load mp3 frame information into memory
rc = GetFrameInfo(
mp4File,
mediaTrackId,
&pFrameHeaders,
&pAduOffsets);
if (!rc) {
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
if (doInterleave) {
u_int32_t maxAduSize =
GetMaxAduSize(mp4File, mediaTrackId);
// compute how many maximum size samples would fit in a packet
samplesPerPacket =
maxPayloadSize / (maxAduSize + 2);
// can't interleave if this number is 0 or 1
if (samplesPerPacket < 2) {
doInterleave = false;
}
}
if (doInterleave) {
// initial estimate of samplesPerGroup
samplesPerGroup = maxLatency / sampleDuration;
// use that to compute an integral stride
u_int8_t stride = samplesPerGroup / samplesPerPacket;
// and then recompute samples per group to deal with rounding
samplesPerGroup = stride * samplesPerPacket;
rc = MP4AV_AudioInterleaveHinter(
mp4File,
mediaTrackId,
hintTrackId,
sampleDuration,
samplesPerGroup / samplesPerPacket, // stride
samplesPerPacket, // bundle
maxPayloadSize,
MP4AV_Rfc3119Concatenator);
} else {
rc = MP4AV_AudioConsecutiveHinter(
mp4File,
mediaTrackId,
hintTrackId,
sampleDuration,
0, // perPacketHeaderSize
2, // perSampleHeaderSize
maxLatency / sampleDuration, // maxSamplesPerPacket
maxPayloadSize,
MP4AV_Rfc3119GetAduSize,
MP4AV_Rfc3119Concatenator,
MP4AV_Rfc3119Fragmenter);
}
// cleanup
free(pFrameHeaders);
pFrameHeaders = NULL;
free(pAduOffsets);
pAduOffsets = NULL;
if (!rc) {
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
return true;
}