1381 Adafruit

PUBLIC DOCUMENT VS1053B OGG VORBIS ENCODER VSMPG VLSI Solution Audio Decoder Project Code: Project Name: VSMPG All information in this document is provided as-is without warranty. Features are subject to change without notice. Revision History Rev. Date Author Description 1.70c 2012-11-16 HH Enhanced streaming documentation. 1.70b 2011-06-29 HH Added .IMG les and example C source code. 1.70 2010-09-09 HH Added Vox and Pause control for mono proles. 1.60d 2010-08-10 HH Corrected Figure 3 on page 15. 1.60c 2010-05-10 HH Enhanced this document, removed XP/Vista demo. 1.60b 2010-05-04 HH Corrected formatting error in this document. 1.60 2010-03-30 HH Enhanced sound quality, added stereo VU meter. 1.50 2009-07-02 HH Added byte alignment, mono channel selection. 1.40 2009-03-24 HH SCI CLOCKF bug x. 1.31 2009-02-26 HH Added Chapter 5.3. 1.30 2009-01-15 HH Added sample counter. 1.21 2008-11-21 HH Corrected contents for SCI CLOCKF. 1.20 2008-11-20 HH Many new features, see Chapter 6. 1.10 2008-05-22 HH Improved quality, many new proles. 1.01 2007-12-21 HH Added XP/Vista demo binary. 1.00 2007-12-03 HH Initial version. Page 1(39) Rev. 1.70c 2012-11-16VS1053B OGG VORBIS ENCODER VSMPG HH Contents VS1053b Ogg Vorbis Encoder Front Page 1 Table of Contents 2 1 Introduction 4 2 Using the Ogg Vorbis Encoder 5 2.1 Limitations and Requirements . 5 2.2 Ogg Vorbis Encoder Proles 5 2.2.1 Prole Groups . 5 2.2.2 Prole Quality Settings . 6 2.3 Running the VS1053b Ogg Vorbis Encoder . 8 2.3.1 VS1053b Ogg Vorbis Encoder Registers . 8 2.3.2 Loading and Starting the Code 9 2.3.3 Reading Ogg Vorbis Data . 10 2.3.4 Reading Additional Data while Recording Ogg Vorbis . 11 2.3.5 Finishing Ogg Vorbis Recording . 11 2.4 Recording Levels and Automatic Gain Control (AGC) 12 2.4.1 Reading the Recording Level . 12 2.4.2 Setting AGC 13 2.4.3 Building a Useful VU Meter 14 2.4.4 Converting from Linear to Decibel Scale . 16 2.4.5 vs1053oggrec.c 17 2.5 Vox and Pause Operation . 22 2.5.1 Vox and Pause Registers . 23 2.5.2 Vox Output to GPIO4 . 23 2.6 Samplerate Considerations 24 2.7 Post-Processing the Recording with VorbisGain . 24 3 The Ogg Vorbis Format 25 3.1 Introduction to Ogg Vorbis . 25 3.1.1 Variable Bit-Rate 25 3.1.2 Transcoding . 26 3.2 Compressing into Ogg Vorbis with a PC . 27 3.2.1 Preparation . 27 3.2.2 Compressing CD-Quality Music 27 3.2.3 Compressing Speech . 29 3.3 Post-Processing with VorbisGain . 30 4 How to Load a Plugin 31 4.1 How to Load a .PLG File 31 4.2 How to Load an .IMG File . 32 4.2.1 Example Microcontroller .IMG File Decoder . 33 5 Building a Streaming System 34 5.1 Sample Counter 35 5.2 End-to-End Delay of a Streaming System 36 Page 2(39) Rev. 1.70c 2012-11-16