test/test-ogg-encode.sgl

1;;; Test OGG Vorbis encoding

2;;;

3;;; Generates a sine wave, encodes to .ogg, then verifies the file

4;;; can be read back.

6(import (sigil core)

7 (sigil math)

8 (sigil audio))

10(define pi 3.14159265358979)

12;; Generate a 1-second 440Hz sine wave (mono, 44100Hz)

13(define sample-rate 44100)

14(define num-samples sample-rate) ;; 1 second

15(define frequency 440.0)

17(display "Generating mono sine wave... ")

18(define samples

19 (let ((v (make-vector num-samples 0.0)))

20 (let loop ((i 0))

21 (when (< i num-samples)

22 (vector-set! v i (* 0.8 (sin (* 2.0 pi frequency (/ i sample-rate)))))

23 (loop (+ i 1))))

24 v))

25(display "OK\n")

27;; Convert to float32 bytevector

28(display "Converting to float buffer... ")

29(define buffer (make-float-buffer samples))

30(display (string-append (number->string (bytevector-length buffer)) " bytes\n"))

32;; Write OGG file using keyword API

33(define output-path "/tmp/test-sigil-ogg-encode.ogg")

34(display (string-append "Encoding mono to " output-path "... "))

35(define result (write-ogg output-path buffer

36 sample-rate: sample-rate

37 channels: 1

38 quality: 0.4))

39(if result

40 (display "OK\n")

41 (begin (display "FAILED\n") (exit 1)))

43;; Verify we can decode the file we just wrote

44(display "Verifying: loading encoded file back... ")

45(define loaded (load-sound output-path))

46(if loaded

47 (display "OK\n")

48 (begin (display "FAILED - could not decode written file\n") (exit 1)))

50;; Test stereo encoding with defaults (sample-rate: 44100, channels: 2, quality: 0.4)

51(display "\nGenerating stereo sine wave... ")

52(define stereo-samples

53 (let ((v (make-vector (* num-samples 2) 0.0)))

54 (let loop ((i 0))

55 (when (< i num-samples)

56 (let ((s (* 0.8 (sin (* 2.0 pi frequency (/ i sample-rate))))))

57 (vector-set! v (* i 2) s)

58 (vector-set! v (+ (* i 2) 1)

59 (* 0.8 (sin (* 2.0 pi (* frequency 1.5) (/ i sample-rate))))))

60 (loop (+ i 1))))

61 v))

62(display "OK\n")

64(define stereo-buffer (make-float-buffer stereo-samples))

65(define stereo-path "/tmp/test-sigil-ogg-encode-stereo.ogg")

66(display (string-append "Encoding stereo to " stereo-path "... "))

67;; Use defaults for stereo (channels: 2 is default)

68(define stereo-result (write-ogg stereo-path stereo-buffer

69 sample-rate: sample-rate))

70(if stereo-result

71 (display "OK\n")

72 (begin (display "FAILED\n") (exit 1)))

74;; Verify stereo file decodes

75(display "Verifying: loading stereo file back... ")

76(define stereo-loaded (load-sound stereo-path))

77(if stereo-loaded

78 (display "OK\n")

79 (begin (display "FAILED - could not decode stereo file\n") (exit 1)))

81(display "\nAll tests passed!\n")