extern "C" u_int8_t MP4AV_AudioGetChannels(
MP4FileHandle mp4File,
MP4TrackId audioTrackId)
{
u_int8_t audioType =
MP4GetTrackEsdsObjectTypeId(mp4File, audioTrackId);
if (audioType == MP4_INVALID_AUDIO_TYPE) {
return 0;
}
if (MP4_IS_MP3_AUDIO_TYPE(audioType)) {
MP4AV_Mp3Header mp3Hdr =
GetMp3Header(mp4File, audioTrackId);
if (mp3Hdr == 0) {
return 0;
}
return MP4AV_Mp3GetChannels(mp3Hdr);
} else if (MP4_IS_AAC_AUDIO_TYPE(audioType)) {
u_int8_t* pAacConfig = NULL;
u_int32_t aacConfigLength;
MP4GetTrackESConfiguration(
mp4File,
audioTrackId,
&pAacConfig,
&aacConfigLength);
if (pAacConfig == NULL || aacConfigLength < 2) {
return 0;
}
u_int8_t channels =
MP4AV_AacConfigGetChannels(pAacConfig);
free(pAacConfig);
return channels;
} else if ((audioType == MP4_PCM16_LITTLE_ENDIAN_AUDIO_TYPE) ||
(audioType == MP4_PCM16_BIG_ENDIAN_AUDIO_TYPE)) {
u_int32_t samplesPerFrame =
MP4GetSampleSize(mp4File, audioTrackId, 1) / 2;
MP4Duration frameDuration =
MP4GetSampleDuration(mp4File, audioTrackId, 1);
if (frameDuration == 0) {
return 0;
}
// assumes track time scale == sampling rate
return samplesPerFrame / frameDuration;
}
return 0;
}
extern "C" u_int16_t MP4AV_AudioGetSamplingWindow(
MP4FileHandle mp4File,
MP4TrackId audioTrackId)
{
u_int8_t audioType =
MP4GetTrackEsdsObjectTypeId(mp4File, audioTrackId);
if (audioType == MP4_INVALID_AUDIO_TYPE) {
return 0;
}
if (MP4_IS_MP3_AUDIO_TYPE(audioType)) {
MP4AV_Mp3Header mp3Hdr =
GetMp3Header(mp4File, audioTrackId);
return MP4AV_Mp3GetHdrSamplingWindow(mp3Hdr);
} else if (MP4_IS_AAC_AUDIO_TYPE(audioType)) {
u_int8_t* pAacConfig = NULL;
u_int32_t aacConfigLength;
MP4GetTrackESConfiguration(
mp4File,
audioTrackId,
&pAacConfig,
&aacConfigLength);
if (pAacConfig == NULL || aacConfigLength < 2) {
return 0;
}
u_int32_t samplingWindow =
MP4AV_AacConfigGetSamplingWindow(pAacConfig);
free(pAacConfig);
return samplingWindow;
} else if ((audioType == MP4_PCM16_LITTLE_ENDIAN_AUDIO_TYPE)||
(audioType == MP4_PCM16_BIG_ENDIAN_AUDIO_TYPE)) {
MP4Duration frameDuration =
MP4GetSampleDuration(mp4File, audioTrackId, 1);
// assumes track time scale == sampling rate
// and constant frame size was used
return frameDuration;
}
return 0;
}
extern "C" u_int32_t MP4AV_AudioGetSamplingRate(
MP4FileHandle mp4File,
MP4TrackId audioTrackId)
{
u_int8_t audioType =
MP4GetTrackEsdsObjectTypeId(mp4File, audioTrackId);
if (audioType == MP4_INVALID_AUDIO_TYPE) {
return 0;
}
if (MP4_IS_MP3_AUDIO_TYPE(audioType)) {
MP4AV_Mp3Header mp3Hdr =
GetMp3Header(mp4File, audioTrackId);
if (mp3Hdr == 0) {
return 0;
}
return MP4AV_Mp3GetHdrSamplingRate(mp3Hdr);
} else if (MP4_IS_AAC_AUDIO_TYPE(audioType)) {
u_int8_t* pAacConfig = NULL;
u_int32_t aacConfigLength;
MP4GetTrackESConfiguration(
mp4File,
audioTrackId,
&pAacConfig,
&aacConfigLength);
if (pAacConfig == NULL || aacConfigLength < 2) {
return 0;
}
u_int32_t samplingRate =
MP4AV_AacConfigGetSamplingRate(pAacConfig);
free(pAacConfig);
return samplingRate;
} else if ((audioType == MP4_PCM16_LITTLE_ENDIAN_AUDIO_TYPE)||
(audioType == MP4_PCM16_BIG_ENDIAN_AUDIO_TYPE)) {
return MP4GetTrackTimeScale(mp4File, audioTrackId);
}
return 0;
}
extern "C" bool MP4AV_RfcIsmaHinter(
MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
bool interleave,
u_int16_t maxPayloadSize)
{
// gather information, and check for validity
u_int32_t numSamples =
MP4GetTrackNumberOfSamples(mp4File, mediaTrackId);
if (numSamples == 0) {
return false;
}
u_int32_t timeScale =
MP4GetTrackTimeScale(mp4File, mediaTrackId);
if (timeScale == 0) {
return false;
}
u_int8_t audioType =
MP4GetTrackEsdsObjectTypeId(mp4File, mediaTrackId);
if (audioType != MP4_MPEG4_AUDIO_TYPE
&& !MP4_IS_AAC_AUDIO_TYPE(audioType)) {
return false;
}
u_int8_t mpeg4AudioType =
MP4GetTrackAudioMpeg4Type(mp4File, mediaTrackId);
if (audioType == MP4_MPEG4_AUDIO_TYPE) {
// check that track contains either MPEG-4 AAC or CELP
if (!MP4_IS_MPEG4_AAC_AUDIO_TYPE(mpeg4AudioType)
&& mpeg4AudioType != MP4_MPEG4_CELP_AUDIO_TYPE) {
return false;
}
}
MP4Duration sampleDuration =
MP4AV_GetAudioSampleDuration(mp4File, mediaTrackId);
if (sampleDuration == MP4_INVALID_DURATION) {
return false;
}
/* get the ES configuration */
u_int8_t* pConfig = NULL;
u_int32_t configSize;
uint8_t channels;
if (MP4GetTrackESConfiguration(mp4File, mediaTrackId,
&pConfig, &configSize) == false)
return false;
if (!pConfig) {
return false;
}
channels = MP4AV_AacConfigGetChannels(pConfig);
/* convert ES Config into ASCII form */
char* sConfig =
MP4BinaryToBase16(pConfig, configSize);
free(pConfig);
if (!sConfig) {
return false;
}
/* create the appropriate SDP attribute */
uint sdpBufLen = strlen(sConfig) + 256;
char* sdpBuf =
(char*)malloc(sdpBufLen);
if (!sdpBuf) {
free(sConfig);
return false;
}
// now add the hint track
MP4TrackId hintTrackId =
MP4AddHintTrack(mp4File, mediaTrackId);
if (hintTrackId == MP4_INVALID_TRACK_ID) {
free(sConfig);
free(sdpBuf);
return false;
}
u_int8_t payloadNumber = MP4_SET_DYNAMIC_PAYLOAD;
char buffer[10];
if (channels != 1) {
snprintf(buffer, sizeof(buffer), "%u", channels);
}
if (MP4SetHintTrackRtpPayload(mp4File, hintTrackId,
"mpeg4-generic", &payloadNumber, 0,
channels != 1 ? buffer : NULL) == false) {
MP4DeleteTrack(mp4File, hintTrackId);
free(sConfig);
free(sdpBuf);
return false;
}
MP4Duration maxLatency;
bool OneByteHeader = false;
if (mpeg4AudioType == MP4_MPEG4_CELP_AUDIO_TYPE) {
snprintf(sdpBuf, sdpBufLen,
"a=fmtp:%u "
"streamtype=5; profile-level-id=15; mode=CELP-vbr; config=%s; "
"SizeLength=6; IndexLength=2; IndexDeltaLength=2; Profile=0;"
"\015\012",
payloadNumber,
sConfig);
// 200 ms max latency for ISMA profile 1
maxLatency = timeScale / 5;
OneByteHeader = true;
} else { // AAC
snprintf(sdpBuf, sdpBufLen,
"a=fmtp:%u "
"streamtype=5; profile-level-id=15; mode=AAC-hbr; config=%s; "
"SizeLength=13; IndexLength=3; IndexDeltaLength=3;"
"\015\012",
payloadNumber,
sConfig);
// 500 ms max latency for ISMA profile 1
maxLatency = timeScale / 2;
}
/* add this to the track's sdp */
bool val = MP4AppendHintTrackSdp(mp4File, hintTrackId, sdpBuf);
free(sConfig);
free(sdpBuf);
if (val == false) {
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
u_int32_t samplesPerPacket = 0;
if (interleave) {
u_int32_t maxSampleSize =
MP4GetTrackMaxSampleSize(mp4File, mediaTrackId);
// compute how many maximum size samples would fit in a packet
samplesPerPacket =
(maxPayloadSize - 2) / (maxSampleSize + 2);
// can't interleave if this number is 0 or 1
if (samplesPerPacket < 2) {
interleave = false;
}
}
bool rc;
if (interleave) {
u_int32_t samplesPerGroup = maxLatency / sampleDuration;
u_int32_t stride;
stride = samplesPerGroup / samplesPerPacket;
if (OneByteHeader && stride > 3) stride = 3;
if (!OneByteHeader && stride > 7) stride = 7;
#if 0
printf("max latency %llu sampleDuration %llu spg %u spp %u strid %u\n",
maxLatency, sampleDuration, samplesPerGroup,
samplesPerPacket, stride);
#endif
rc = MP4AV_AudioInterleaveHinter(
mp4File,
mediaTrackId,
hintTrackId,
sampleDuration,
stride, // stride
samplesPerPacket, // bundle
maxPayloadSize,
MP4AV_RfcIsmaConcatenator);
} else {
rc = MP4AV_AudioConsecutiveHinter(
mp4File,
mediaTrackId,
hintTrackId,
sampleDuration,
2, // perPacketHeaderSize
2, // perSampleHeaderSize
maxLatency / sampleDuration, // maxSamplesPerPacket
maxPayloadSize,
MP4GetSampleSize,
MP4AV_RfcIsmaConcatenator,
MP4AV_RfcIsmaFragmenter);
}
if (!rc) {
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
return true;
}