media_packet_ptr lame_encoder_impl_internal::encode(const audio_data * _AudioData)
{
static const size_t mp3TimeBase = 14112000; // Least common multiple of 44100 and 32000
const int predSamplesInLame = lame_get_mf_samples_to_encode( m_Lame.get() );
// from lame:
// The required mp3buf_size can be computed from num_samples,
// samplerate and encoding rate, but here is a worst case estimate:
// mp3buf_size in bytes = 1.25*num_samples + 7200
const size_t samplesCount = (_AudioData) ? _AudioData->get_samples_count() : 0;
const size_t bufSize = static_cast<size_t>( 1.25 * samplesCount ) + 7200 ;
uint8_t * buffer = m_Buffer.get_buffer( bufSize );
int lameRet = 0;
if (_AudioData)
{
const size_t channelsCount = _AudioData->get_channels_count();
if (channelsCount == 1)
{
lameRet = lame_encode_buffer(
m_Lame.get(),
(short*)_AudioData->get_raw_data(),
(short*)_AudioData->get_raw_data(),
_AudioData->get_samples_count(),
buffer,
bufSize);
}
else
{
lameRet = lame_encode_buffer_interleaved(
m_Lame.get(),
(short*)_AudioData->get_raw_data(),
_AudioData->get_samples_count(),
buffer,
bufSize);
}
}
else
{
lameRet = lame_encode_flush(m_Lame.get(), buffer, bufSize) ;
}
const int samplesEncoded = predSamplesInLame + samplesCount - lame_get_mf_samples_to_encode( m_Lame.get() );
m_TotalSamplesEncoded += samplesEncoded;
common_media_packet2_ptr mediaPacket = common_media_packet2_ptr( new common_media_packet2() );
mediaPacket->setter()->set_data(buffer, lameRet, bufferAllocNew);
mediaPacket->setter()->set_media_type(DT_AVMEDIA_TYPE_AUDIO);
mediaPacket->setter()->set_time_base(dt_rational_t(1, mp3TimeBase));
mediaPacket->setter()->set_duration( samplesEncoded * (mp3TimeBase / get_input_sample_rate()) );
const dt_ts_t ts = m_TotalSamplesEncoded * (mp3TimeBase / get_input_sample_rate());
mediaPacket->setter()->set_pts( ts );
mediaPacket->setter()->set_dts( ts );
return mediaPacket;
}
ff_media_packet::ff_media_packet(AVPacketPtr _AVPacket, dt_media_type_t _MediaType): media_packet(new ff_media_packet_impl(_AVPacket, _MediaType, dt_rational_t()))
{
}
ff_media_packet::ff_media_packet(AVPacketPtr _AVPacket): media_packet(new ff_media_packet_impl(_AVPacket, DT_AVMEDIA_TYPE_UNKNOWN, dt_rational_t()))
{
}
virtual dt_rational_t get_frame_rate() const { return dt_rational_t(); }
virtual dt_rational_t get_time_base() const { return dt_rational_t(); }
