Encoder testing
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+56
-32
@@ -11,12 +11,29 @@
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opus-encoder-finish)
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;; libopusenc handles the Ogg container, OpusHead and OpusTags. The Racket
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;; side only feeds interleaved signed 16-bit PCM to ope_encoder_write().
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;; side feeds interleaved floating-point PCM to ope_encoder_write_float().
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;; The input rate passed to ope_encoder_create_file is the source PCM rate;
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;; libopusenc performs the required Opus resampling internally.
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;; Load libogg and libopus explicitly before libopusenc. This matters on
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;; Windows, where libopusenc.dll may not reliably find its dependent DLLs
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;; unless they have already been resolved through the same search path.
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(define libogg
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(get-lib (case (system-type 'os)
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[(windows) '("ogg")]
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[else '("ogg" "libogg")])
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'(#f)))
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(define libopus
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(get-lib (case (system-type 'os)
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[(windows) '("opus")]
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[else '("opus" "libopus")])
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'(#f)))
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(define libopusenc
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(get-lib (case (system-type 'os)
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[(windows) '("opusenc")]
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[else '("opusenc" "libopusenc")])
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[(windows) '("libopusenc")]
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[else '("opusenc" "libopusenc")])
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'(#f)))
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(define _OggOpusComments (_cpointer/null 'ogg-opus-comments))
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@@ -37,7 +54,7 @@
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(_fun _string/utf-8 _OggOpusComments _int32 _int _int (err : (_ptr o _int))
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-> (enc : _OggOpusEnc)
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-> (values enc err))))
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(define ope_encoder_write (ffi-proc "ope_encoder_write" (_fun _OggOpusEnc _bytes _int -> _int)))
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(define ope_encoder_write_float (ffi-proc "ope_encoder_write_float" (_fun _OggOpusEnc _pointer _int -> _int)))
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(define ope_encoder_drain (ffi-proc "ope_encoder_drain" (_fun _OggOpusEnc -> _int)))
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(define ope_encoder_destroy (ffi-proc "ope_encoder_destroy" (_fun _OggOpusEnc -> _void)))
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(define ope_strerror (ffi-proc "ope_strerror" (_fun _int -> _string/utf-8)))
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@@ -56,8 +73,8 @@
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(define OPUS_SIGNAL_MUSIC 3002)
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(define (opus-encoder-available?)
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(and libopusenc ope_comments_create ope_comments_destroy ope_encoder_create_file
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ope_encoder_write ope_encoder_drain ope_encoder_destroy ope_strerror #t))
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(and libogg libopus libopusenc ope_comments_create ope_comments_destroy ope_encoder_create_file
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ope_encoder_write_float ope_encoder_drain ope_encoder_destroy ope_strerror #t))
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(define-struct opus-encoder-handle (enc comments settings format file) #:transparent)
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@@ -89,21 +106,24 @@
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(complexity . 10)
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(comment-padding . 512))))
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(define (valid-opus-rate? rate)
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(or (= rate 8000) (= rate 12000) (= rate 16000) (= rate 24000) (= rate 48000)))
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(define (signal->int v)
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(cond [(or (eq? v 'auto) (eq? v #f)) OPUS_AUTO]
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[(eq? v 'voice) OPUS_SIGNAL_VOICE]
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[(eq? v 'music) OPUS_SIGNAL_MUSIC]
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[else (raise-argument-error 'opus-signal "(or/c 'auto 'voice 'music)" v)]))
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(define (source-value v source)
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(if (eq? v 'source) source v))
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(define (opus-encoder-prepare-settings settings format)
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(let* ((h (hash-merge (opus-encoder-default-settings) settings))
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(rate (hash-ref/default h 'sample-rate (hash-ref format 'sample-rate)))
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(channels (hash-ref/default h 'channels (hash-ref format 'channels))))
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(unless (valid-opus-rate? rate)
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(error 'opus-encoder-open "Opus input sample rate must be 8000, 12000, 16000, 24000 or 48000 Hz; got ~a. Resample before calling libopusenc." rate))
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(rate (source-value (hash-ref/default h 'sample-rate (hash-ref format 'sample-rate))
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(hash-ref format 'sample-rate)))
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(channels (source-value (hash-ref/default h 'channels (hash-ref format 'channels))
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(hash-ref format 'channels))))
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;; Do not apply the low-level libopus sample-rate restriction here.
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;; libopusenc accepts the input rate and performs the required resampling
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;; internally; 44100 Hz input is therefore valid.
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(when (> channels 2)
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(error 'opus-encoder-open "this first direct libopusenc backend only supports mono/stereo input; got ~a channels" channels))
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(hash-set! h 'sample-rate rate)
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@@ -137,7 +157,8 @@
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(hash-keys ch))))))
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(define (opus-encoder-open output-file settings format)
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(unless (opus-encoder-available?) (error 'opus-encoder-open "libopusenc could not be loaded"))
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(unless (opus-encoder-available?)
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(error 'opus-encoder-open "libopusenc or one of its dependent libraries (ogg/opus) could not be loaded"))
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(let* ((file (if (path? output-file) (path->string output-file) output-file))
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(resolved (opus-encoder-prepare-settings settings format))
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(comments (ope_comments_create)))
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@@ -151,35 +172,38 @@
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(make-opus-encoder-handle enc comments resolved format file))))
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(define (native-signed-ref bs start bytes)
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(integer-bytes->integer bs #t (system-big-endian?) start (+ start bytes)))
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;; Racket's integer-bytes->integer only supports 1, 2, 4 and 8 bytes.
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;; The FLAC decoder legitimately produces 24-bit PCM as three bytes per
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;; sample, so use the package helper that handles that case.
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(int-bytes->integer bs #t (system-big-endian?) start (+ start bytes)))
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(define (sample->s16 sample in-bits)
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(cond [(> in-bits 16) (arithmetic-shift sample (- 16 in-bits))]
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[(< in-bits 16) (arithmetic-shift sample (- 16 in-bits))]
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[else sample]))
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(define (sample->float sample in-bits)
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(let* ((scale (expt 2 (sub1 in-bits)))
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(v (/ sample scale)))
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(cond [(< v -1.0) -1.0]
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[(> v 1.0) 1.0]
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[else (exact->inexact v)])))
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(define (write-s16-native! out offset sample)
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(integer->integer-bytes sample 2 #t (system-big-endian?) out offset))
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(define (pcm-bytes->s16 buffer size in-bits)
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(define (pcm-bytes->float-pointer buffer size in-bits)
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(let* ((in-bytes (quotient in-bits 8))
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(sample-count (quotient size in-bytes))
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(out (make-bytes (* sample-count 2))))
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(ptr (malloc _float sample-count 'atomic-interior)))
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(for ([i (in-range sample-count)])
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(let* ((in-off (* i in-bytes))
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(out-off (* i 2))
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(sample (native-signed-ref buffer in-off in-bytes)))
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(write-s16-native! out out-off (sample->s16 sample in-bits))))
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out))
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(ptr-set! ptr _float i (sample->float sample in-bits))))
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(values ptr sample-count)))
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(define (opus-encoder-write handle buf-info buffer buf-len)
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(let* ((settings (opus-encoder-handle-settings handle))
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(channels (hash-ref settings 'channels))
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(in-bits (hash-ref/default buf-info 'bits-per-sample 16))
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(pcm (if (= in-bits 16) buffer (pcm-bytes->s16 buffer buf-len in-bits)))
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(frames (quotient (quotient (bytes-length pcm) 2) channels)))
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(check-ope 'opus-encoder-write (ope_encoder_write (opus-encoder-handle-enc handle) pcm frames))
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frames))
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(in-bits (hash-ref/default buf-info 'pcm-bits-per-sample
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(hash-ref/default buf-info 'bits-per-sample 16))))
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(let-values (((pcm sample-count) (pcm-bytes->float-pointer buffer buf-len in-bits)))
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(let ((frames (quotient sample-count channels)))
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(check-ope 'opus-encoder-write
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(ope_encoder_write_float (opus-encoder-handle-enc handle) pcm frames))
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frames))))
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(define (opus-encoder-finish handle)
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(dynamic-wind
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