ref: 91c3d6d0e3f82f9ffddd3fd2e95ea7fafb403111
dir: /plugins/in_mp4/aactrack.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, 2001. All Rights Reserved.
*
* Contributor(s):
* Dave Mackie [email protected]
*/
/*
* Notes:
* - file formatted with tabstops == 4 spaces
*/
#include <mpeg4ip.h>
#include <mp4.h>
#include "mp4av.h"
#include "aac2mp4.h"
#define ADTS_HEADER_MAX_SIZE 10 /* bytes */
static u_int8_t firstHeader[ADTS_HEADER_MAX_SIZE];
/*
* hdr must point to at least ADTS_HEADER_MAX_SIZE bytes of memory
*/
static bool LoadNextAdtsHeader(FILE* inFile, u_int8_t* hdr)
{
u_int state = 0;
u_int dropped = 0;
u_int hdrByteSize = ADTS_HEADER_MAX_SIZE;
while (1) {
/* read a byte */
u_int8_t b;
if (fread(&b, 1, 1, inFile) == 0) {
return false;
}
/* header is complete, return it */
if (state == hdrByteSize - 1) {
hdr[state] = b;
if (dropped > 0) {
fprintf(stderr, "Warning: dropped %u input bytes\n", dropped);
}
return true;
}
/* collect requisite number of bytes, no constraints on data */
if (state >= 2) {
hdr[state++] = b;
} else {
/* have first byte, check if we have 1111X00X */
if (state == 1) {
if ((b & 0xF6) == 0xF0) {
hdr[state] = b;
state = 2;
/* compute desired header size */
hdrByteSize = MP4AV_AdtsGetHeaderByteSize(hdr);
} else {
state = 0;
}
}
/* initial state, looking for 11111111 */
if (state == 0) {
if (b == 0xFF) {
hdr[state] = b;
state = 1;
} else {
/* else drop it */
dropped++;
}
}
}
}
}
/*
* Load the next frame from the file
* into the supplied buffer, which better be large enough!
*
* Note: Frames are padded to byte boundaries
*/
static bool LoadNextAacFrame(FILE* inFile, u_int8_t* pBuf, u_int32_t* pBufSize, bool stripAdts)
{
u_int16_t frameSize;
u_int16_t hdrBitSize, hdrByteSize;
u_int8_t hdrBuf[ADTS_HEADER_MAX_SIZE];
/* get the next AAC frame header, more or less */
if (!LoadNextAdtsHeader(inFile, hdrBuf)) {
return false;
}
/* get frame size from header */
frameSize = MP4AV_AdtsGetFrameSize(hdrBuf);
/* get header size in bits and bytes from header */
hdrBitSize = MP4AV_AdtsGetHeaderBitSize(hdrBuf);
hdrByteSize = MP4AV_AdtsGetHeaderByteSize(hdrBuf);
/* adjust the frame size to what remains to be read */
frameSize -= hdrByteSize;
if (stripAdts) {
if ((hdrBitSize % 8) == 0) {
/* header is byte aligned, i.e. MPEG-2 ADTS */
/* read the frame data into the buffer */
if (fread(pBuf, 1, frameSize, inFile) != frameSize) {
return false;
}
(*pBufSize) = frameSize;
} else {
/* header is not byte aligned, i.e. MPEG-4 ADTS */
int i;
u_int8_t newByte;
int upShift = hdrBitSize % 8;
int downShift = 8 - upShift;
pBuf[0] = hdrBuf[hdrBitSize / 8] << upShift;
for (i = 0; i < frameSize; i++) {
if (fread(&newByte, 1, 1, inFile) != 1) {
return false;
}
pBuf[i] |= (newByte >> downShift);
pBuf[i+1] = (newByte << upShift);
}
(*pBufSize) = frameSize + 1;
}
} else { /* don't strip ADTS headers */
memcpy(pBuf, hdrBuf, hdrByteSize);
if (fread(&pBuf[hdrByteSize], 1, frameSize, inFile) != frameSize) {
return false;
}
}
return true;
}
static bool GetFirstHeader(FILE* inFile)
{
/* read file until we find an audio frame */
fpos_t curPos;
/* already read first header */
if (firstHeader[0] == 0xff) {
return true;
}
/* remember where we are */
fgetpos(inFile, &curPos);
/* go back to start of file */
rewind(inFile);
if (!LoadNextAdtsHeader(inFile, firstHeader)) {
return false;
}
/* reposition the file to where we were */
fsetpos(inFile, &curPos);
return true;
}
MP4TrackId AacCreator(MP4FileHandle mp4File, FILE* inFile)
{
// collect all the necessary meta information
u_int32_t samplesPerSecond;
u_int8_t mpegVersion;
u_int8_t profile;
u_int8_t channelConfig;
if (!GetFirstHeader(inFile)) {
return MP4_INVALID_TRACK_ID;
}
samplesPerSecond = MP4AV_AdtsGetSamplingRate(firstHeader);
mpegVersion = MP4AV_AdtsGetVersion(firstHeader);
profile = MP4AV_AdtsGetProfile(firstHeader);
channelConfig = MP4AV_AdtsGetChannels(firstHeader);
u_int8_t audioType = MP4_INVALID_AUDIO_TYPE;
switch (mpegVersion) {
case 0:
audioType = MP4_MPEG4_AUDIO_TYPE;
break;
case 1:
switch (profile) {
case 0:
audioType = MP4_MPEG2_AAC_MAIN_AUDIO_TYPE;
break;
case 1:
audioType = MP4_MPEG2_AAC_LC_AUDIO_TYPE;
break;
case 2:
audioType = MP4_MPEG2_AAC_SSR_AUDIO_TYPE;
break;
case 3:
return MP4_INVALID_TRACK_ID;
}
break;
}
// add the new audio track
MP4TrackId trackId =
MP4AddAudioTrack(mp4File,
samplesPerSecond, 1024, audioType);
if (trackId == MP4_INVALID_TRACK_ID) {
return MP4_INVALID_TRACK_ID;
}
if (MP4GetNumberOfTracks(mp4File, MP4_AUDIO_TRACK_TYPE) == 1) {
MP4SetAudioProfileLevel(mp4File, 0x0F);
}
u_int8_t* pConfig = NULL;
u_int32_t configLength = 0;
MP4AV_AacGetConfiguration(
&pConfig,
&configLength,
profile,
samplesPerSecond,
channelConfig);
if (!MP4SetTrackESConfiguration(mp4File, trackId,
pConfig, configLength)) {
MP4DeleteTrack(mp4File, trackId);
return MP4_INVALID_TRACK_ID;
}
// parse the ADTS frames, and write the MP4 samples
u_int8_t sampleBuffer[8 * 1024];
u_int32_t sampleSize = sizeof(sampleBuffer);
MP4SampleId sampleId = 1;
while (LoadNextAacFrame(inFile, sampleBuffer, &sampleSize, true)) {
if (!MP4WriteSample(mp4File, trackId, sampleBuffer, sampleSize)) {
MP4DeleteTrack(mp4File, trackId);
return MP4_INVALID_TRACK_ID;
}
sampleId++;
sampleSize = sizeof(sampleBuffer);
}
return trackId;
}