FRAME-BASED AUDIO CODING WITH ADDITIONAL FILTERBANK TO SUPPRESS ALIASING ARTIFACTS AT FRAME BOUNDRIES

摘要

SEVERAL AUDIO SIGNAL PROCESSING TECHNIQUES MAY BE USED IN VARIOUS COMBINATIONS TO IMPROVE THE QUALITY OF AUDIO REPRESENTED BY AN INFORMATION STREAM FORMED BY SPLICE EDITING TWO OR MORE OTHER INFORMATION STREAMS. THE TECHNIQUES ARE PARTICULARLY USEFUL IN APPLICATIONS THAT BUNDLE AUDIO INFORMATION WITH VIDEO INFORMATION. IN ONE TECHNIQUE, GAIN-CONTROL WORDS CONVEYED WITH THE AUDIO INFORMATION STREAM ARE USED TO INTERPOLATE PLAYBACK SOUND LEVELS ACROSS A SPLICE. IN ANOTHER TECHNIQUE, SPECIAL FILTERBANKS (205-207) OR FORMS OF TDAC TRANSFORMS ARE USED TO SUPPRESS ALIASING ARTIFACTS ON EITHER SIDE OF A SPLICE. IN YET ANOTHER TECHNIQUE, SPECIAL FILTERBANKS OR CROSSFADE WINDOW FUNCTIONS ARE USED TO OPTIMIZE THE ATTENUATION OF SPECTRAL SPLATTER CREATED AT A SPLICE. IN A FURTHER TECHNIQUE, AUDIO SAMPLE RATES ARE CONVERTED ACCORDING TO FRAME LENGTHS AND RATES TO ALLOW AUDIO INFORMATION TO BE BUNDLED WITH, FOR EXAMPLE, VIDEO INFORMATION. IN YET A FURTHER TECHNIQUE, AUDIO BLOCKS (11-17) ARE DYNAMICALLY ALIGNED SO THE PROPER SYNCHRONIZATION CAN BE MAINTAINED ACROSS A SPLICE. AN EXAMPLE FOR 48 KHZ AUDIO WITH NTSC VIDEO IS DISCUSSED. FIGURE 5A