| /* |
| * Copyright (c) 2012 Pavel Koshevoy <pkoshevoy at gmail dot com> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /** |
| * @file |
| * tempo scaling audio filter -- an implementation of WSOLA algorithm |
| * |
| * Based on MIT licensed yaeAudioTempoFilter.h and yaeAudioFragment.h |
| * from Apprentice Video player by Pavel Koshevoy. |
| * https://sourceforge.net/projects/apprenticevideo/ |
| * |
| * An explanation of SOLA algorithm is available at |
| * http://www.surina.net/article/time-and-pitch-scaling.html |
| * |
| * WSOLA is very similar to SOLA, only one major difference exists between |
| * these algorithms. SOLA shifts audio fragments along the output stream, |
| * where as WSOLA shifts audio fragments along the input stream. |
| * |
| * The advantage of WSOLA algorithm is that the overlap region size is |
| * always the same, therefore the blending function is constant and |
| * can be precomputed. |
| */ |
| |
| #include <float.h> |
| #include "libavcodec/avfft.h" |
| #include "libavutil/avassert.h" |
| #include "libavutil/avstring.h" |
| #include "libavutil/channel_layout.h" |
| #include "libavutil/eval.h" |
| #include "libavutil/opt.h" |
| #include "libavutil/samplefmt.h" |
| #include "avfilter.h" |
| #include "audio.h" |
| #include "internal.h" |
| |
| /** |
| * A fragment of audio waveform |
| */ |
| typedef struct { |
| // index of the first sample of this fragment in the overall waveform; |
| // 0: input sample position |
| // 1: output sample position |
| int64_t position[2]; |
| |
| // original packed multi-channel samples: |
| uint8_t *data; |
| |
| // number of samples in this fragment: |
| int nsamples; |
| |
| // rDFT transform of the down-mixed mono fragment, used for |
| // fast waveform alignment via correlation in frequency domain: |
| FFTSample *xdat; |
| } AudioFragment; |
| |
| /** |
| * Filter state machine states |
| */ |
| typedef enum { |
| YAE_LOAD_FRAGMENT, |
| YAE_ADJUST_POSITION, |
| YAE_RELOAD_FRAGMENT, |
| YAE_OUTPUT_OVERLAP_ADD, |
| YAE_FLUSH_OUTPUT, |
| } FilterState; |
| |
| /** |
| * Filter state machine |
| */ |
| typedef struct { |
| const AVClass *class; |
| |
| // ring-buffer of input samples, necessary because some times |
| // input fragment position may be adjusted backwards: |
| uint8_t *buffer; |
| |
| // ring-buffer maximum capacity, expressed in sample rate time base: |
| int ring; |
| |
| // ring-buffer house keeping: |
| int size; |
| int head; |
| int tail; |
| |
| // 0: input sample position corresponding to the ring buffer tail |
| // 1: output sample position |
| int64_t position[2]; |
| |
| // sample format: |
| enum AVSampleFormat format; |
| |
| // number of channels: |
| int channels; |
| |
| // row of bytes to skip from one sample to next, across multple channels; |
| // stride = (number-of-channels * bits-per-sample-per-channel) / 8 |
| int stride; |
| |
| // fragment window size, power-of-two integer: |
| int window; |
| |
| // Hann window coefficients, for feathering |
| // (blending) the overlapping fragment region: |
| float *hann; |
| |
| // tempo scaling factor: |
| double tempo; |
| |
| // a snapshot of previous fragment input and output position values |
| // captured when the tempo scale factor was set most recently: |
| int64_t origin[2]; |
| |
| // current/previous fragment ring-buffer: |
| AudioFragment frag[2]; |
| |
| // current fragment index: |
| uint64_t nfrag; |
| |
| // current state: |
| FilterState state; |
| |
| // for fast correlation calculation in frequency domain: |
| RDFTContext *real_to_complex; |
| RDFTContext *complex_to_real; |
| FFTSample *correlation; |
| |
| // for managing AVFilterPad.request_frame and AVFilterPad.filter_frame |
| AVFrame *dst_buffer; |
| uint8_t *dst; |
| uint8_t *dst_end; |
| uint64_t nsamples_in; |
| uint64_t nsamples_out; |
| } ATempoContext; |
| |
| #define OFFSET(x) offsetof(ATempoContext, x) |
| |
| static const AVOption atempo_options[] = { |
| { "tempo", "set tempo scale factor", |
| OFFSET(tempo), AV_OPT_TYPE_DOUBLE, { .dbl = 1.0 }, 0.5, 2.0, |
| AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM }, |
| { NULL } |
| }; |
| |
| AVFILTER_DEFINE_CLASS(atempo); |
| |
| inline static AudioFragment *yae_curr_frag(ATempoContext *atempo) |
| { |
| return &atempo->frag[atempo->nfrag % 2]; |
| } |
| |
| inline static AudioFragment *yae_prev_frag(ATempoContext *atempo) |
| { |
| return &atempo->frag[(atempo->nfrag + 1) % 2]; |
| } |
| |
| /** |
| * Reset filter to initial state, do not deallocate existing local buffers. |
| */ |
| static void yae_clear(ATempoContext *atempo) |
| { |
| atempo->size = 0; |
| atempo->head = 0; |
| atempo->tail = 0; |
| |
| atempo->nfrag = 0; |
| atempo->state = YAE_LOAD_FRAGMENT; |
| |
| atempo->position[0] = 0; |
| atempo->position[1] = 0; |
| |
| atempo->origin[0] = 0; |
| atempo->origin[1] = 0; |
| |
| atempo->frag[0].position[0] = 0; |
| atempo->frag[0].position[1] = 0; |
| atempo->frag[0].nsamples = 0; |
| |
| atempo->frag[1].position[0] = 0; |
| atempo->frag[1].position[1] = 0; |
| atempo->frag[1].nsamples = 0; |
| |
| // shift left position of 1st fragment by half a window |
| // so that no re-normalization would be required for |
| // the left half of the 1st fragment: |
| atempo->frag[0].position[0] = -(int64_t)(atempo->window / 2); |
| atempo->frag[0].position[1] = -(int64_t)(atempo->window / 2); |
| |
| av_frame_free(&atempo->dst_buffer); |
| atempo->dst = NULL; |
| atempo->dst_end = NULL; |
| |
| atempo->nsamples_in = 0; |
| atempo->nsamples_out = 0; |
| } |
| |
| /** |
| * Reset filter to initial state and deallocate all buffers. |
| */ |
| static void yae_release_buffers(ATempoContext *atempo) |
| { |
| yae_clear(atempo); |
| |
| av_freep(&atempo->frag[0].data); |
| av_freep(&atempo->frag[1].data); |
| av_freep(&atempo->frag[0].xdat); |
| av_freep(&atempo->frag[1].xdat); |
| |
| av_freep(&atempo->buffer); |
| av_freep(&atempo->hann); |
| av_freep(&atempo->correlation); |
| |
| av_rdft_end(atempo->real_to_complex); |
| atempo->real_to_complex = NULL; |
| |
| av_rdft_end(atempo->complex_to_real); |
| atempo->complex_to_real = NULL; |
| } |
| |
| /* av_realloc is not aligned enough; fortunately, the data does not need to |
| * be preserved */ |
| #define RE_MALLOC_OR_FAIL(field, field_size) \ |
| do { \ |
| av_freep(&field); \ |
| field = av_malloc(field_size); \ |
| if (!field) { \ |
| yae_release_buffers(atempo); \ |
| return AVERROR(ENOMEM); \ |
| } \ |
| } while (0) |
| |
| /** |
| * Prepare filter for processing audio data of given format, |
| * sample rate and number of channels. |
| */ |
| static int yae_reset(ATempoContext *atempo, |
| enum AVSampleFormat format, |
| int sample_rate, |
| int channels) |
| { |
| const int sample_size = av_get_bytes_per_sample(format); |
| uint32_t nlevels = 0; |
| uint32_t pot; |
| int i; |
| |
| atempo->format = format; |
| atempo->channels = channels; |
| atempo->stride = sample_size * channels; |
| |
| // pick a segment window size: |
| atempo->window = sample_rate / 24; |
| |
| // adjust window size to be a power-of-two integer: |
| nlevels = av_log2(atempo->window); |
| pot = 1 << nlevels; |
| av_assert0(pot <= atempo->window); |
| |
| if (pot < atempo->window) { |
| atempo->window = pot * 2; |
| nlevels++; |
| } |
| |
| // initialize audio fragment buffers: |
| RE_MALLOC_OR_FAIL(atempo->frag[0].data, atempo->window * atempo->stride); |
| RE_MALLOC_OR_FAIL(atempo->frag[1].data, atempo->window * atempo->stride); |
| RE_MALLOC_OR_FAIL(atempo->frag[0].xdat, atempo->window * sizeof(FFTComplex)); |
| RE_MALLOC_OR_FAIL(atempo->frag[1].xdat, atempo->window * sizeof(FFTComplex)); |
| |
| // initialize rDFT contexts: |
| av_rdft_end(atempo->real_to_complex); |
| atempo->real_to_complex = NULL; |
| |
| av_rdft_end(atempo->complex_to_real); |
| atempo->complex_to_real = NULL; |
| |
| atempo->real_to_complex = av_rdft_init(nlevels + 1, DFT_R2C); |
| if (!atempo->real_to_complex) { |
| yae_release_buffers(atempo); |
| return AVERROR(ENOMEM); |
| } |
| |
| atempo->complex_to_real = av_rdft_init(nlevels + 1, IDFT_C2R); |
| if (!atempo->complex_to_real) { |
| yae_release_buffers(atempo); |
| return AVERROR(ENOMEM); |
| } |
| |
| RE_MALLOC_OR_FAIL(atempo->correlation, atempo->window * sizeof(FFTComplex)); |
| |
| atempo->ring = atempo->window * 3; |
| RE_MALLOC_OR_FAIL(atempo->buffer, atempo->ring * atempo->stride); |
| |
| // initialize the Hann window function: |
| RE_MALLOC_OR_FAIL(atempo->hann, atempo->window * sizeof(float)); |
| |
| for (i = 0; i < atempo->window; i++) { |
| double t = (double)i / (double)(atempo->window - 1); |
| double h = 0.5 * (1.0 - cos(2.0 * M_PI * t)); |
| atempo->hann[i] = (float)h; |
| } |
| |
| yae_clear(atempo); |
| return 0; |
| } |
| |
| static int yae_set_tempo(AVFilterContext *ctx, const char *arg_tempo) |
| { |
| const AudioFragment *prev; |
| ATempoContext *atempo = ctx->priv; |
| char *tail = NULL; |
| double tempo = av_strtod(arg_tempo, &tail); |
| |
| if (tail && *tail) { |
| av_log(ctx, AV_LOG_ERROR, "Invalid tempo value '%s'\n", arg_tempo); |
| return AVERROR(EINVAL); |
| } |
| |
| if (tempo < 0.5 || tempo > 2.0) { |
| av_log(ctx, AV_LOG_ERROR, "Tempo value %f exceeds [0.5, 2.0] range\n", |
| tempo); |
| return AVERROR(EINVAL); |
| } |
| |
| prev = yae_prev_frag(atempo); |
| atempo->origin[0] = prev->position[0] + atempo->window / 2; |
| atempo->origin[1] = prev->position[1] + atempo->window / 2; |
| atempo->tempo = tempo; |
| return 0; |
| } |
| |
| /** |
| * A helper macro for initializing complex data buffer with scalar data |
| * of a given type. |
| */ |
| #define yae_init_xdat(scalar_type, scalar_max) \ |
| do { \ |
| const uint8_t *src_end = src + \ |
| frag->nsamples * atempo->channels * sizeof(scalar_type); \ |
| \ |
| FFTSample *xdat = frag->xdat; \ |
| scalar_type tmp; \ |
| \ |
| if (atempo->channels == 1) { \ |
| for (; src < src_end; xdat++) { \ |
| tmp = *(const scalar_type *)src; \ |
| src += sizeof(scalar_type); \ |
| \ |
| *xdat = (FFTSample)tmp; \ |
| } \ |
| } else { \ |
| FFTSample s, max, ti, si; \ |
| int i; \ |
| \ |
| for (; src < src_end; xdat++) { \ |
| tmp = *(const scalar_type *)src; \ |
| src += sizeof(scalar_type); \ |
| \ |
| max = (FFTSample)tmp; \ |
| s = FFMIN((FFTSample)scalar_max, \ |
| (FFTSample)fabsf(max)); \ |
| \ |
| for (i = 1; i < atempo->channels; i++) { \ |
| tmp = *(const scalar_type *)src; \ |
| src += sizeof(scalar_type); \ |
| \ |
| ti = (FFTSample)tmp; \ |
| si = FFMIN((FFTSample)scalar_max, \ |
| (FFTSample)fabsf(ti)); \ |
| \ |
| if (s < si) { \ |
| s = si; \ |
| max = ti; \ |
| } \ |
| } \ |
| \ |
| *xdat = max; \ |
| } \ |
| } \ |
| } while (0) |
| |
| /** |
| * Initialize complex data buffer of a given audio fragment |
| * with down-mixed mono data of appropriate scalar type. |
| */ |
| static void yae_downmix(ATempoContext *atempo, AudioFragment *frag) |
| { |
| // shortcuts: |
| const uint8_t *src = frag->data; |
| |
| // init complex data buffer used for FFT and Correlation: |
| memset(frag->xdat, 0, sizeof(FFTComplex) * atempo->window); |
| |
| if (atempo->format == AV_SAMPLE_FMT_U8) { |
| yae_init_xdat(uint8_t, 127); |
| } else if (atempo->format == AV_SAMPLE_FMT_S16) { |
| yae_init_xdat(int16_t, 32767); |
| } else if (atempo->format == AV_SAMPLE_FMT_S32) { |
| yae_init_xdat(int, 2147483647); |
| } else if (atempo->format == AV_SAMPLE_FMT_FLT) { |
| yae_init_xdat(float, 1); |
| } else if (atempo->format == AV_SAMPLE_FMT_DBL) { |
| yae_init_xdat(double, 1); |
| } |
| } |
| |
| /** |
| * Populate the internal data buffer on as-needed basis. |
| * |
| * @return |
| * 0 if requested data was already available or was successfully loaded, |
| * AVERROR(EAGAIN) if more input data is required. |
| */ |
| static int yae_load_data(ATempoContext *atempo, |
| const uint8_t **src_ref, |
| const uint8_t *src_end, |
| int64_t stop_here) |
| { |
| // shortcut: |
| const uint8_t *src = *src_ref; |
| const int read_size = stop_here - atempo->position[0]; |
| |
| if (stop_here <= atempo->position[0]) { |
| return 0; |
| } |
| |
| // samples are not expected to be skipped: |
| av_assert0(read_size <= atempo->ring); |
| |
| while (atempo->position[0] < stop_here && src < src_end) { |
| int src_samples = (src_end - src) / atempo->stride; |
| |
| // load data piece-wise, in order to avoid complicating the logic: |
| int nsamples = FFMIN(read_size, src_samples); |
| int na; |
| int nb; |
| |
| nsamples = FFMIN(nsamples, atempo->ring); |
| na = FFMIN(nsamples, atempo->ring - atempo->tail); |
| nb = FFMIN(nsamples - na, atempo->ring); |
| |
| if (na) { |
| uint8_t *a = atempo->buffer + atempo->tail * atempo->stride; |
| memcpy(a, src, na * atempo->stride); |
| |
| src += na * atempo->stride; |
| atempo->position[0] += na; |
| |
| atempo->size = FFMIN(atempo->size + na, atempo->ring); |
| atempo->tail = (atempo->tail + na) % atempo->ring; |
| atempo->head = |
| atempo->size < atempo->ring ? |
| atempo->tail - atempo->size : |
| atempo->tail; |
| } |
| |
| if (nb) { |
| uint8_t *b = atempo->buffer; |
| memcpy(b, src, nb * atempo->stride); |
| |
| src += nb * atempo->stride; |
| atempo->position[0] += nb; |
| |
| atempo->size = FFMIN(atempo->size + nb, atempo->ring); |
| atempo->tail = (atempo->tail + nb) % atempo->ring; |
| atempo->head = |
| atempo->size < atempo->ring ? |
| atempo->tail - atempo->size : |
| atempo->tail; |
| } |
| } |
| |
| // pass back the updated source buffer pointer: |
| *src_ref = src; |
| |
| // sanity check: |
| av_assert0(atempo->position[0] <= stop_here); |
| |
| return atempo->position[0] == stop_here ? 0 : AVERROR(EAGAIN); |
| } |
| |
| /** |
| * Populate current audio fragment data buffer. |
| * |
| * @return |
| * 0 when the fragment is ready, |
| * AVERROR(EAGAIN) if more input data is required. |
| */ |
| static int yae_load_frag(ATempoContext *atempo, |
| const uint8_t **src_ref, |
| const uint8_t *src_end) |
| { |
| // shortcuts: |
| AudioFragment *frag = yae_curr_frag(atempo); |
| uint8_t *dst; |
| int64_t missing, start, zeros; |
| uint32_t nsamples; |
| const uint8_t *a, *b; |
| int i0, i1, n0, n1, na, nb; |
| |
| int64_t stop_here = frag->position[0] + atempo->window; |
| if (src_ref && yae_load_data(atempo, src_ref, src_end, stop_here) != 0) { |
| return AVERROR(EAGAIN); |
| } |
| |
| // calculate the number of samples we don't have: |
| missing = |
| stop_here > atempo->position[0] ? |
| stop_here - atempo->position[0] : 0; |
| |
| nsamples = |
| missing < (int64_t)atempo->window ? |
| (uint32_t)(atempo->window - missing) : 0; |
| |
| // setup the output buffer: |
| frag->nsamples = nsamples; |
| dst = frag->data; |
| |
| start = atempo->position[0] - atempo->size; |
| zeros = 0; |
| |
| if (frag->position[0] < start) { |
| // what we don't have we substitute with zeros: |
| zeros = FFMIN(start - frag->position[0], (int64_t)nsamples); |
| av_assert0(zeros != nsamples); |
| |
| memset(dst, 0, zeros * atempo->stride); |
| dst += zeros * atempo->stride; |
| } |
| |
| if (zeros == nsamples) { |
| return 0; |
| } |
| |
| // get the remaining data from the ring buffer: |
| na = (atempo->head < atempo->tail ? |
| atempo->tail - atempo->head : |
| atempo->ring - atempo->head); |
| |
| nb = atempo->head < atempo->tail ? 0 : atempo->tail; |
| |
| // sanity check: |
| av_assert0(nsamples <= zeros + na + nb); |
| |
| a = atempo->buffer + atempo->head * atempo->stride; |
| b = atempo->buffer; |
| |
| i0 = frag->position[0] + zeros - start; |
| i1 = i0 < na ? 0 : i0 - na; |
| |
| n0 = i0 < na ? FFMIN(na - i0, (int)(nsamples - zeros)) : 0; |
| n1 = nsamples - zeros - n0; |
| |
| if (n0) { |
| memcpy(dst, a + i0 * atempo->stride, n0 * atempo->stride); |
| dst += n0 * atempo->stride; |
| } |
| |
| if (n1) { |
| memcpy(dst, b + i1 * atempo->stride, n1 * atempo->stride); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * Prepare for loading next audio fragment. |
| */ |
| static void yae_advance_to_next_frag(ATempoContext *atempo) |
| { |
| const double fragment_step = atempo->tempo * (double)(atempo->window / 2); |
| |
| const AudioFragment *prev; |
| AudioFragment *frag; |
| |
| atempo->nfrag++; |
| prev = yae_prev_frag(atempo); |
| frag = yae_curr_frag(atempo); |
| |
| frag->position[0] = prev->position[0] + (int64_t)fragment_step; |
| frag->position[1] = prev->position[1] + atempo->window / 2; |
| frag->nsamples = 0; |
| } |
| |
| /** |
| * Calculate cross-correlation via rDFT. |
| * |
| * Multiply two vectors of complex numbers (result of real_to_complex rDFT) |
| * and transform back via complex_to_real rDFT. |
| */ |
| static void yae_xcorr_via_rdft(FFTSample *xcorr, |
| RDFTContext *complex_to_real, |
| const FFTComplex *xa, |
| const FFTComplex *xb, |
| const int window) |
| { |
| FFTComplex *xc = (FFTComplex *)xcorr; |
| int i; |
| |
| // NOTE: first element requires special care -- Given Y = rDFT(X), |
| // Im(Y[0]) and Im(Y[N/2]) are always zero, therefore av_rdft_calc |
| // stores Re(Y[N/2]) in place of Im(Y[0]). |
| |
| xc->re = xa->re * xb->re; |
| xc->im = xa->im * xb->im; |
| xa++; |
| xb++; |
| xc++; |
| |
| for (i = 1; i < window; i++, xa++, xb++, xc++) { |
| xc->re = (xa->re * xb->re + xa->im * xb->im); |
| xc->im = (xa->im * xb->re - xa->re * xb->im); |
| } |
| |
| // apply inverse rDFT: |
| av_rdft_calc(complex_to_real, xcorr); |
| } |
| |
| /** |
| * Calculate alignment offset for given fragment |
| * relative to the previous fragment. |
| * |
| * @return alignment offset of current fragment relative to previous. |
| */ |
| static int yae_align(AudioFragment *frag, |
| const AudioFragment *prev, |
| const int window, |
| const int delta_max, |
| const int drift, |
| FFTSample *correlation, |
| RDFTContext *complex_to_real) |
| { |
| int best_offset = -drift; |
| FFTSample best_metric = -FLT_MAX; |
| FFTSample *xcorr; |
| |
| int i0; |
| int i1; |
| int i; |
| |
| yae_xcorr_via_rdft(correlation, |
| complex_to_real, |
| (const FFTComplex *)prev->xdat, |
| (const FFTComplex *)frag->xdat, |
| window); |
| |
| // identify search window boundaries: |
| i0 = FFMAX(window / 2 - delta_max - drift, 0); |
| i0 = FFMIN(i0, window); |
| |
| i1 = FFMIN(window / 2 + delta_max - drift, window - window / 16); |
| i1 = FFMAX(i1, 0); |
| |
| // identify cross-correlation peaks within search window: |
| xcorr = correlation + i0; |
| |
| for (i = i0; i < i1; i++, xcorr++) { |
| FFTSample metric = *xcorr; |
| |
| // normalize: |
| FFTSample drifti = (FFTSample)(drift + i); |
| metric *= drifti * (FFTSample)(i - i0) * (FFTSample)(i1 - i); |
| |
| if (metric > best_metric) { |
| best_metric = metric; |
| best_offset = i - window / 2; |
| } |
| } |
| |
| return best_offset; |
| } |
| |
| /** |
| * Adjust current fragment position for better alignment |
| * with previous fragment. |
| * |
| * @return alignment correction. |
| */ |
| static int yae_adjust_position(ATempoContext *atempo) |
| { |
| const AudioFragment *prev = yae_prev_frag(atempo); |
| AudioFragment *frag = yae_curr_frag(atempo); |
| |
| const double prev_output_position = |
| (double)(prev->position[1] - atempo->origin[1] + atempo->window / 2); |
| |
| const double ideal_output_position = |
| (double)(prev->position[0] - atempo->origin[0] + atempo->window / 2) / |
| atempo->tempo; |
| |
| const int drift = (int)(prev_output_position - ideal_output_position); |
| |
| const int delta_max = atempo->window / 2; |
| const int correction = yae_align(frag, |
| prev, |
| atempo->window, |
| delta_max, |
| drift, |
| atempo->correlation, |
| atempo->complex_to_real); |
| |
| if (correction) { |
| // adjust fragment position: |
| frag->position[0] -= correction; |
| |
| // clear so that the fragment can be reloaded: |
| frag->nsamples = 0; |
| } |
| |
| return correction; |
| } |
| |
| /** |
| * A helper macro for blending the overlap region of previous |
| * and current audio fragment. |
| */ |
| #define yae_blend(scalar_type) \ |
| do { \ |
| const scalar_type *aaa = (const scalar_type *)a; \ |
| const scalar_type *bbb = (const scalar_type *)b; \ |
| \ |
| scalar_type *out = (scalar_type *)dst; \ |
| scalar_type *out_end = (scalar_type *)dst_end; \ |
| int64_t i; \ |
| \ |
| for (i = 0; i < overlap && out < out_end; \ |
| i++, atempo->position[1]++, wa++, wb++) { \ |
| float w0 = *wa; \ |
| float w1 = *wb; \ |
| int j; \ |
| \ |
| for (j = 0; j < atempo->channels; \ |
| j++, aaa++, bbb++, out++) { \ |
| float t0 = (float)*aaa; \ |
| float t1 = (float)*bbb; \ |
| \ |
| *out = \ |
| frag->position[0] + i < 0 ? \ |
| *aaa : \ |
| (scalar_type)(t0 * w0 + t1 * w1); \ |
| } \ |
| } \ |
| dst = (uint8_t *)out; \ |
| } while (0) |
| |
| /** |
| * Blend the overlap region of previous and current audio fragment |
| * and output the results to the given destination buffer. |
| * |
| * @return |
| * 0 if the overlap region was completely stored in the dst buffer, |
| * AVERROR(EAGAIN) if more destination buffer space is required. |
| */ |
| static int yae_overlap_add(ATempoContext *atempo, |
| uint8_t **dst_ref, |
| uint8_t *dst_end) |
| { |
| // shortcuts: |
| const AudioFragment *prev = yae_prev_frag(atempo); |
| const AudioFragment *frag = yae_curr_frag(atempo); |
| |
| const int64_t start_here = FFMAX(atempo->position[1], |
| frag->position[1]); |
| |
| const int64_t stop_here = FFMIN(prev->position[1] + prev->nsamples, |
| frag->position[1] + frag->nsamples); |
| |
| const int64_t overlap = stop_here - start_here; |
| |
| const int64_t ia = start_here - prev->position[1]; |
| const int64_t ib = start_here - frag->position[1]; |
| |
| const float *wa = atempo->hann + ia; |
| const float *wb = atempo->hann + ib; |
| |
| const uint8_t *a = prev->data + ia * atempo->stride; |
| const uint8_t *b = frag->data + ib * atempo->stride; |
| |
| uint8_t *dst = *dst_ref; |
| |
| av_assert0(start_here <= stop_here && |
| frag->position[1] <= start_here && |
| overlap <= frag->nsamples); |
| |
| if (atempo->format == AV_SAMPLE_FMT_U8) { |
| yae_blend(uint8_t); |
| } else if (atempo->format == AV_SAMPLE_FMT_S16) { |
| yae_blend(int16_t); |
| } else if (atempo->format == AV_SAMPLE_FMT_S32) { |
| yae_blend(int); |
| } else if (atempo->format == AV_SAMPLE_FMT_FLT) { |
| yae_blend(float); |
| } else if (atempo->format == AV_SAMPLE_FMT_DBL) { |
| yae_blend(double); |
| } |
| |
| // pass-back the updated destination buffer pointer: |
| *dst_ref = dst; |
| |
| return atempo->position[1] == stop_here ? 0 : AVERROR(EAGAIN); |
| } |
| |
| /** |
| * Feed as much data to the filter as it is able to consume |
| * and receive as much processed data in the destination buffer |
| * as it is able to produce or store. |
| */ |
| static void |
| yae_apply(ATempoContext *atempo, |
| const uint8_t **src_ref, |
| const uint8_t *src_end, |
| uint8_t **dst_ref, |
| uint8_t *dst_end) |
| { |
| while (1) { |
| if (atempo->state == YAE_LOAD_FRAGMENT) { |
| // load additional data for the current fragment: |
| if (yae_load_frag(atempo, src_ref, src_end) != 0) { |
| break; |
| } |
| |
| // down-mix to mono: |
| yae_downmix(atempo, yae_curr_frag(atempo)); |
| |
| // apply rDFT: |
| av_rdft_calc(atempo->real_to_complex, yae_curr_frag(atempo)->xdat); |
| |
| // must load the second fragment before alignment can start: |
| if (!atempo->nfrag) { |
| yae_advance_to_next_frag(atempo); |
| continue; |
| } |
| |
| atempo->state = YAE_ADJUST_POSITION; |
| } |
| |
| if (atempo->state == YAE_ADJUST_POSITION) { |
| // adjust position for better alignment: |
| if (yae_adjust_position(atempo)) { |
| // reload the fragment at the corrected position, so that the |
| // Hann window blending would not require normalization: |
| atempo->state = YAE_RELOAD_FRAGMENT; |
| } else { |
| atempo->state = YAE_OUTPUT_OVERLAP_ADD; |
| } |
| } |
| |
| if (atempo->state == YAE_RELOAD_FRAGMENT) { |
| // load additional data if necessary due to position adjustment: |
| if (yae_load_frag(atempo, src_ref, src_end) != 0) { |
| break; |
| } |
| |
| // down-mix to mono: |
| yae_downmix(atempo, yae_curr_frag(atempo)); |
| |
| // apply rDFT: |
| av_rdft_calc(atempo->real_to_complex, yae_curr_frag(atempo)->xdat); |
| |
| atempo->state = YAE_OUTPUT_OVERLAP_ADD; |
| } |
| |
| if (atempo->state == YAE_OUTPUT_OVERLAP_ADD) { |
| // overlap-add and output the result: |
| if (yae_overlap_add(atempo, dst_ref, dst_end) != 0) { |
| break; |
| } |
| |
| // advance to the next fragment, repeat: |
| yae_advance_to_next_frag(atempo); |
| atempo->state = YAE_LOAD_FRAGMENT; |
| } |
| } |
| } |
| |
| /** |
| * Flush any buffered data from the filter. |
| * |
| * @return |
| * 0 if all data was completely stored in the dst buffer, |
| * AVERROR(EAGAIN) if more destination buffer space is required. |
| */ |
| static int yae_flush(ATempoContext *atempo, |
| uint8_t **dst_ref, |
| uint8_t *dst_end) |
| { |
| AudioFragment *frag = yae_curr_frag(atempo); |
| int64_t overlap_end; |
| int64_t start_here; |
| int64_t stop_here; |
| int64_t offset; |
| |
| const uint8_t *src; |
| uint8_t *dst; |
| |
| int src_size; |
| int dst_size; |
| int nbytes; |
| |
| atempo->state = YAE_FLUSH_OUTPUT; |
| |
| if (atempo->position[0] == frag->position[0] + frag->nsamples && |
| atempo->position[1] == frag->position[1] + frag->nsamples) { |
| // the current fragment is already flushed: |
| return 0; |
| } |
| |
| if (frag->position[0] + frag->nsamples < atempo->position[0]) { |
| // finish loading the current (possibly partial) fragment: |
| yae_load_frag(atempo, NULL, NULL); |
| |
| if (atempo->nfrag) { |
| // down-mix to mono: |
| yae_downmix(atempo, frag); |
| |
| // apply rDFT: |
| av_rdft_calc(atempo->real_to_complex, frag->xdat); |
| |
| // align current fragment to previous fragment: |
| if (yae_adjust_position(atempo)) { |
| // reload the current fragment due to adjusted position: |
| yae_load_frag(atempo, NULL, NULL); |
| } |
| } |
| } |
| |
| // flush the overlap region: |
| overlap_end = frag->position[1] + FFMIN(atempo->window / 2, |
| frag->nsamples); |
| |
| while (atempo->position[1] < overlap_end) { |
| if (yae_overlap_add(atempo, dst_ref, dst_end) != 0) { |
| return AVERROR(EAGAIN); |
| } |
| } |
| |
| // check whether all of the input samples have been consumed: |
| if (frag->position[0] + frag->nsamples < atempo->position[0]) { |
| yae_advance_to_next_frag(atempo); |
| return AVERROR(EAGAIN); |
| } |
| |
| // flush the remainder of the current fragment: |
| start_here = FFMAX(atempo->position[1], overlap_end); |
| stop_here = frag->position[1] + frag->nsamples; |
| offset = start_here - frag->position[1]; |
| av_assert0(start_here <= stop_here && frag->position[1] <= start_here); |
| |
| src = frag->data + offset * atempo->stride; |
| dst = (uint8_t *)*dst_ref; |
| |
| src_size = (int)(stop_here - start_here) * atempo->stride; |
| dst_size = dst_end - dst; |
| nbytes = FFMIN(src_size, dst_size); |
| |
| memcpy(dst, src, nbytes); |
| dst += nbytes; |
| |
| atempo->position[1] += (nbytes / atempo->stride); |
| |
| // pass-back the updated destination buffer pointer: |
| *dst_ref = (uint8_t *)dst; |
| |
| return atempo->position[1] == stop_here ? 0 : AVERROR(EAGAIN); |
| } |
| |
| static av_cold int init(AVFilterContext *ctx) |
| { |
| ATempoContext *atempo = ctx->priv; |
| atempo->format = AV_SAMPLE_FMT_NONE; |
| atempo->state = YAE_LOAD_FRAGMENT; |
| return 0; |
| } |
| |
| static av_cold void uninit(AVFilterContext *ctx) |
| { |
| ATempoContext *atempo = ctx->priv; |
| yae_release_buffers(atempo); |
| } |
| |
| static int query_formats(AVFilterContext *ctx) |
| { |
| AVFilterChannelLayouts *layouts = NULL; |
| AVFilterFormats *formats = NULL; |
| |
| // WSOLA necessitates an internal sliding window ring buffer |
| // for incoming audio stream. |
| // |
| // Planar sample formats are too cumbersome to store in a ring buffer, |
| // therefore planar sample formats are not supported. |
| // |
| static const enum AVSampleFormat sample_fmts[] = { |
| AV_SAMPLE_FMT_U8, |
| AV_SAMPLE_FMT_S16, |
| AV_SAMPLE_FMT_S32, |
| AV_SAMPLE_FMT_FLT, |
| AV_SAMPLE_FMT_DBL, |
| AV_SAMPLE_FMT_NONE |
| }; |
| int ret; |
| |
| layouts = ff_all_channel_layouts(); |
| if (!layouts) { |
| return AVERROR(ENOMEM); |
| } |
| ret = ff_set_common_channel_layouts(ctx, layouts); |
| if (ret < 0) |
| return ret; |
| |
| formats = ff_make_format_list(sample_fmts); |
| if (!formats) { |
| return AVERROR(ENOMEM); |
| } |
| ret = ff_set_common_formats(ctx, formats); |
| if (ret < 0) |
| return ret; |
| |
| formats = ff_all_samplerates(); |
| if (!formats) { |
| return AVERROR(ENOMEM); |
| } |
| return ff_set_common_samplerates(ctx, formats); |
| } |
| |
| static int config_props(AVFilterLink *inlink) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| ATempoContext *atempo = ctx->priv; |
| |
| enum AVSampleFormat format = inlink->format; |
| int sample_rate = (int)inlink->sample_rate; |
| int channels = av_get_channel_layout_nb_channels(inlink->channel_layout); |
| |
| return yae_reset(atempo, format, sample_rate, channels); |
| } |
| |
| static int push_samples(ATempoContext *atempo, |
| AVFilterLink *outlink, |
| int n_out) |
| { |
| int ret; |
| |
| atempo->dst_buffer->sample_rate = outlink->sample_rate; |
| atempo->dst_buffer->nb_samples = n_out; |
| |
| // adjust the PTS: |
| atempo->dst_buffer->pts = |
| av_rescale_q(atempo->nsamples_out, |
| (AVRational){ 1, outlink->sample_rate }, |
| outlink->time_base); |
| |
| ret = ff_filter_frame(outlink, atempo->dst_buffer); |
| atempo->dst_buffer = NULL; |
| atempo->dst = NULL; |
| atempo->dst_end = NULL; |
| if (ret < 0) |
| return ret; |
| |
| atempo->nsamples_out += n_out; |
| return 0; |
| } |
| |
| static int filter_frame(AVFilterLink *inlink, AVFrame *src_buffer) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| ATempoContext *atempo = ctx->priv; |
| AVFilterLink *outlink = ctx->outputs[0]; |
| |
| int ret = 0; |
| int n_in = src_buffer->nb_samples; |
| int n_out = (int)(0.5 + ((double)n_in) / atempo->tempo); |
| |
| const uint8_t *src = src_buffer->data[0]; |
| const uint8_t *src_end = src + n_in * atempo->stride; |
| |
| while (src < src_end) { |
| if (!atempo->dst_buffer) { |
| atempo->dst_buffer = ff_get_audio_buffer(outlink, n_out); |
| if (!atempo->dst_buffer) |
| return AVERROR(ENOMEM); |
| av_frame_copy_props(atempo->dst_buffer, src_buffer); |
| |
| atempo->dst = atempo->dst_buffer->data[0]; |
| atempo->dst_end = atempo->dst + n_out * atempo->stride; |
| } |
| |
| yae_apply(atempo, &src, src_end, &atempo->dst, atempo->dst_end); |
| |
| if (atempo->dst == atempo->dst_end) { |
| int n_samples = ((atempo->dst - atempo->dst_buffer->data[0]) / |
| atempo->stride); |
| ret = push_samples(atempo, outlink, n_samples); |
| if (ret < 0) |
| goto end; |
| } |
| } |
| |
| atempo->nsamples_in += n_in; |
| end: |
| av_frame_free(&src_buffer); |
| return ret; |
| } |
| |
| static int request_frame(AVFilterLink *outlink) |
| { |
| AVFilterContext *ctx = outlink->src; |
| ATempoContext *atempo = ctx->priv; |
| int ret; |
| |
| ret = ff_request_frame(ctx->inputs[0]); |
| |
| if (ret == AVERROR_EOF) { |
| // flush the filter: |
| int n_max = atempo->ring; |
| int n_out; |
| int err = AVERROR(EAGAIN); |
| |
| while (err == AVERROR(EAGAIN)) { |
| if (!atempo->dst_buffer) { |
| atempo->dst_buffer = ff_get_audio_buffer(outlink, n_max); |
| if (!atempo->dst_buffer) |
| return AVERROR(ENOMEM); |
| |
| atempo->dst = atempo->dst_buffer->data[0]; |
| atempo->dst_end = atempo->dst + n_max * atempo->stride; |
| } |
| |
| err = yae_flush(atempo, &atempo->dst, atempo->dst_end); |
| |
| n_out = ((atempo->dst - atempo->dst_buffer->data[0]) / |
| atempo->stride); |
| |
| if (n_out) { |
| ret = push_samples(atempo, outlink, n_out); |
| } |
| } |
| |
| av_frame_free(&atempo->dst_buffer); |
| atempo->dst = NULL; |
| atempo->dst_end = NULL; |
| |
| return AVERROR_EOF; |
| } |
| |
| return ret; |
| } |
| |
| static int process_command(AVFilterContext *ctx, |
| const char *cmd, |
| const char *arg, |
| char *res, |
| int res_len, |
| int flags) |
| { |
| return !strcmp(cmd, "tempo") ? yae_set_tempo(ctx, arg) : AVERROR(ENOSYS); |
| } |
| |
| static const AVFilterPad atempo_inputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| .filter_frame = filter_frame, |
| .config_props = config_props, |
| }, |
| { NULL } |
| }; |
| |
| static const AVFilterPad atempo_outputs[] = { |
| { |
| .name = "default", |
| .request_frame = request_frame, |
| .type = AVMEDIA_TYPE_AUDIO, |
| }, |
| { NULL } |
| }; |
| |
| AVFilter ff_af_atempo = { |
| .name = "atempo", |
| .description = NULL_IF_CONFIG_SMALL("Adjust audio tempo."), |
| .init = init, |
| .uninit = uninit, |
| .query_formats = query_formats, |
| .process_command = process_command, |
| .priv_size = sizeof(ATempoContext), |
| .priv_class = &atempo_class, |
| .inputs = atempo_inputs, |
| .outputs = atempo_outputs, |
| }; |