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_Rfc3016LatmHinter (MP4FileHandle mp4File,
MP4TrackId mediaTrackId,
u_int16_t maxPayloadSize)
{
u_int32_t numSamples = MP4GetTrackNumberOfSamples(mp4File, mediaTrackId);
u_int32_t maxSampleSize = MP4GetTrackMaxSampleSize(mp4File, mediaTrackId);
MP4Duration sampleDuration =
MP4AV_GetAudioSampleDuration(mp4File, mediaTrackId);
if (sampleDuration == MP4_INVALID_DURATION) {
return false;
}
if (numSamples == 0 || maxSampleSize == 0) {
return false;
}
/* get the mpeg4 video configuration */
u_int8_t* pAudioSpecificConfig;
u_int32_t AudioSpecificConfigSize;
if (MP4GetTrackESConfiguration(mp4File, mediaTrackId,
&pAudioSpecificConfig,
&AudioSpecificConfigSize) == false)
return false;
if (pAudioSpecificConfig == NULL ||
AudioSpecificConfigSize == 0) return false;
uint8_t channels = MP4AV_AacConfigGetChannels(pAudioSpecificConfig);
uint32_t freq = MP4AV_AacConfigGetSamplingRate(pAudioSpecificConfig);
uint8_t type = MP4AV_AacConfigGetAudioObjectType(pAudioSpecificConfig);
uint8_t *pConfig;
uint32_t configSize;
MP4AV_LatmGetConfiguration(&pConfig, &configSize,
pAudioSpecificConfig, AudioSpecificConfigSize);
free(pAudioSpecificConfig);
if (pConfig == NULL || configSize == 0) {
CHECK_AND_FREE(pConfig);
return false;
}
MP4TrackId hintTrackId =
MP4AddHintTrack(mp4File, mediaTrackId);
if (hintTrackId == MP4_INVALID_TRACK_ID) {
free(pConfig);
return false;
}
u_int8_t payloadNumber = MP4_SET_DYNAMIC_PAYLOAD;
char buffer[10];
if (channels != 1) {
snprintf(buffer, sizeof(buffer), "%u", channels);
}
/* convert it into ASCII form */
char* sConfig = MP4BinaryToBase16(pConfig, configSize);
free(pConfig);
if (sConfig == NULL ||
MP4SetHintTrackRtpPayload(mp4File, hintTrackId,
"MP4A-LATM", &payloadNumber, 0,
channels != 1 ? buffer : NULL) == false) {
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
uint32_t profile_level;
// from gpac code
switch (type) {
case 2:
if (channels <= 2) profile_level = freq <= 24000 ? 0x28 : 0x29;
else profile_level = freq <= 48000 ? 0x2a : 0x2b;
break;
case 5:
if (channels <= 2) profile_level = freq < 24000 ? 0x2c : 0x2d;
else profile_level = freq <= 48000 ? 0x2e : 0x2f;
break;
default:
if (channels <= 2) profile_level = freq < 24000 ? 0x0e : 0x0f;
else profile_level = 0x10;
break;
}
/* create the appropriate SDP attribute */
char* sdpBuf = (char*)malloc(strlen(sConfig) + 128);
if (sdpBuf == NULL) {
free(sConfig);
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
snprintf(sdpBuf,
strlen(sConfig) + 128,
"a=fmtp:%u profile-level-id=%u; cpresent=0; config=%s;\015\012",
payloadNumber,
profile_level,
sConfig);
/* 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;
}
for (MP4SampleId sampleId = 1; sampleId <= numSamples; sampleId++) {
uint8_t buffer[32];
uint32_t offset = 0;
uint32_t sampleSize =
MP4GetSampleSize(mp4File, mediaTrackId, sampleId);
uint32_t size_left = sampleSize;
while (size_left > 0) {
if (size_left > 0xff) {
size_left -= 0xff;
buffer[offset] = 0xff;
} else {
buffer[offset] = size_left;
size_left = 0;
}
offset++;
}
if (MP4AddRtpHint(mp4File, hintTrackId) == false ||
MP4AddRtpPacket(mp4File, hintTrackId, true) == false ||
MP4AddRtpImmediateData(mp4File, hintTrackId,
buffer, offset) == false ||
MP4AddRtpSampleData(mp4File, hintTrackId,
sampleId, 0, sampleSize) == false ||
MP4WriteRtpHint(mp4File, hintTrackId, sampleDuration) == false) {
MP4DeleteTrack(mp4File, hintTrackId);
return false;
}
}
return true;
}
