Controlling Volume by Tracks

Samples Directory

/cri/pc/samples/criatomex/control_track_volume

Data used in the sample

/cri/common/smpdata/criatomex/

• InterleavedMultiTrack.hca
  

Sample Description

Atom library has a mechanism to handle multichannel sound data as multi-track sound data.

For example, when you play 6ch sound data, it is treated as 5.1ch sound data (data in which each channel corresponds to L, R, C, LFE, Ls, and Rs) by default.
However, by using the criAtomExPlayer_SetTrackInfo function , you can control 6ch sound data as monophonic 6 track sound data or stereo 3 track sound data.

    :
/* Define the number of channels for each track */
/* Note: In this sample, 8ch sound data is treated as 2-channel 4-track data.  */
const CriSint32 channels_per_track[4] = { 2, 2, 2, 2 };
    :
/* Create a Voice Pool which can play back 8ch HCA data */
criAtomExVoicePool_SetDefaultConfigForHcaVoicePool(&voice_pool_config);
voice_pool_config.player_config.max_channels = 8;
app_obj->voice_pool
    = criAtomExVoicePool_AllocateHcaVoicePool(&voice_pool_config, NULL, 0);
 
/* Create a player */
app_obj->player = criAtomExPlayer_Create(NULL, NULL, 0);
 
/* Set format information of the sound data to play */
/* Note: Since the data to be played back is 2-channel 4-track = 8,             */
/*       specify 8 to the criAtomExPlayer_SetNumChannels function.      */
criAtomExPlayer_SetFormat(app_obj->player, CRIATOMEX_FORMAT_HCA);
criAtomExPlayer_SetNumChannels(app_obj->player, 8);
criAtomExPlayer_SetSamplingRate(app_obj->player, 48000);
 
/* Set track information of the sound data */
/* Note: In the following code, 2-channel 4-track is specified.  */
criAtomExPlayer_SetTrackInfo(app_obj->player, NUM_TRACKS, channels_per_track);
 
/* Set sound data */
criAtomExPlayer_SetFile(app_obj->player, NULL, PATH FILE);
 
/* Start playback */
criAtomExPlayer_Start(app_obj->player);
    :

By using above settings, AtomEx players plays back 8ch sound data as stereo 4-track sound data.
You can control volume for each track independently using the criAtomExPlayer_SetTrackVolume function.

    :
/* Mute sound other than track 2 */
criAtomExPlayer_SetTrackVolume(app_obj->player, 0, 0.0f);
criAtomExPlayer_SetTrackVolume(app_obj->player, 1, 0.0f);
criAtomExPlayer_SetTrackVolume(app_obj->player, 2, 1.0f);
criAtomExPlayer_SetTrackVolume(app_obj->player, 3, 0.0f);
criAtomExPlayer_UpdateAll(app_obj->player);
    :