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author | Stefano Sabatini <stefasab@gmail.com> | 2023-01-15 16:43:06 +0100 |
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committer | Stefano Sabatini <stefasab@gmail.com> | 2023-02-11 17:49:01 +0100 |
commit | cd8211527efbb9cad19db1c0d033da0749836e43 (patch) | |
tree | faaec1ef7473f0149c3abb31574cbd7eaae797c2 /doc/examples/resampling_audio.c | |
parent | 0a69ca656b7178c260f68d50d07b2e16a073050c (diff) | |
download | ffmpeg-cd8211527efbb9cad19db1c0d033da0749836e43.tar.gz |
examples: rename resampling audio to resample_audio
Diffstat (limited to 'doc/examples/resampling_audio.c')
-rw-r--r-- | doc/examples/resampling_audio.c | 216 |
1 files changed, 0 insertions, 216 deletions
diff --git a/doc/examples/resampling_audio.c b/doc/examples/resampling_audio.c deleted file mode 100644 index 9f1521a5a5..0000000000 --- a/doc/examples/resampling_audio.c +++ /dev/null @@ -1,216 +0,0 @@ -/* - * Copyright (c) 2012 Stefano Sabatini - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN - * THE SOFTWARE. - */ - -/** - * @example resampling_audio.c - * libswresample API use example. - */ - -#include <libavutil/opt.h> -#include <libavutil/channel_layout.h> -#include <libavutil/samplefmt.h> -#include <libswresample/swresample.h> - -static int get_format_from_sample_fmt(const char **fmt, - enum AVSampleFormat sample_fmt) -{ - int i; - struct sample_fmt_entry { - enum AVSampleFormat sample_fmt; const char *fmt_be, *fmt_le; - } sample_fmt_entries[] = { - { AV_SAMPLE_FMT_U8, "u8", "u8" }, - { AV_SAMPLE_FMT_S16, "s16be", "s16le" }, - { AV_SAMPLE_FMT_S32, "s32be", "s32le" }, - { AV_SAMPLE_FMT_FLT, "f32be", "f32le" }, - { AV_SAMPLE_FMT_DBL, "f64be", "f64le" }, - }; - *fmt = NULL; - - for (i = 0; i < FF_ARRAY_ELEMS(sample_fmt_entries); i++) { - struct sample_fmt_entry *entry = &sample_fmt_entries[i]; - if (sample_fmt == entry->sample_fmt) { - *fmt = AV_NE(entry->fmt_be, entry->fmt_le); - return 0; - } - } - - fprintf(stderr, - "Sample format %s not supported as output format\n", - av_get_sample_fmt_name(sample_fmt)); - return AVERROR(EINVAL); -} - -/** - * Fill dst buffer with nb_samples, generated starting from t. - */ -static void fill_samples(double *dst, int nb_samples, int nb_channels, int sample_rate, double *t) -{ - int i, j; - double tincr = 1.0 / sample_rate, *dstp = dst; - const double c = 2 * M_PI * 440.0; - - /* generate sin tone with 440Hz frequency and duplicated channels */ - for (i = 0; i < nb_samples; i++) { - *dstp = sin(c * *t); - for (j = 1; j < nb_channels; j++) - dstp[j] = dstp[0]; - dstp += nb_channels; - *t += tincr; - } -} - -int main(int argc, char **argv) -{ - AVChannelLayout src_ch_layout = AV_CHANNEL_LAYOUT_STEREO, dst_ch_layout = AV_CHANNEL_LAYOUT_SURROUND; - int src_rate = 48000, dst_rate = 44100; - uint8_t **src_data = NULL, **dst_data = NULL; - int src_nb_channels = 0, dst_nb_channels = 0; - int src_linesize, dst_linesize; - int src_nb_samples = 1024, dst_nb_samples, max_dst_nb_samples; - enum AVSampleFormat src_sample_fmt = AV_SAMPLE_FMT_DBL, dst_sample_fmt = AV_SAMPLE_FMT_S16; - const char *dst_filename = NULL; - FILE *dst_file; - int dst_bufsize; - const char *fmt; - struct SwrContext *swr_ctx; - char buf[64]; - double t; - int ret; - - if (argc != 2) { - fprintf(stderr, "Usage: %s output_file\n" - "API example program to show how to resample an audio stream with libswresample.\n" - "This program generates a series of audio frames, resamples them to a specified " - "output format and rate and saves them to an output file named output_file.\n", - argv[0]); - exit(1); - } - dst_filename = argv[1]; - - dst_file = fopen(dst_filename, "wb"); - if (!dst_file) { - fprintf(stderr, "Could not open destination file %s\n", dst_filename); - exit(1); - } - - /* create resampler context */ - swr_ctx = swr_alloc(); - if (!swr_ctx) { - fprintf(stderr, "Could not allocate resampler context\n"); - ret = AVERROR(ENOMEM); - goto end; - } - - /* set options */ - av_opt_set_chlayout(swr_ctx, "in_chlayout", &src_ch_layout, 0); - av_opt_set_int(swr_ctx, "in_sample_rate", src_rate, 0); - av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt", src_sample_fmt, 0); - - av_opt_set_chlayout(swr_ctx, "out_chlayout", &dst_ch_layout, 0); - av_opt_set_int(swr_ctx, "out_sample_rate", dst_rate, 0); - av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt", dst_sample_fmt, 0); - - /* initialize the resampling context */ - if ((ret = swr_init(swr_ctx)) < 0) { - fprintf(stderr, "Failed to initialize the resampling context\n"); - goto end; - } - - /* allocate source and destination samples buffers */ - - src_nb_channels = src_ch_layout.nb_channels; - ret = av_samples_alloc_array_and_samples(&src_data, &src_linesize, src_nb_channels, - src_nb_samples, src_sample_fmt, 0); - if (ret < 0) { - fprintf(stderr, "Could not allocate source samples\n"); - goto end; - } - - /* compute the number of converted samples: buffering is avoided - * ensuring that the output buffer will contain at least all the - * converted input samples */ - max_dst_nb_samples = dst_nb_samples = - av_rescale_rnd(src_nb_samples, dst_rate, src_rate, AV_ROUND_UP); - - /* buffer is going to be directly written to a rawaudio file, no alignment */ - dst_nb_channels = dst_ch_layout.nb_channels; - ret = av_samples_alloc_array_and_samples(&dst_data, &dst_linesize, dst_nb_channels, - dst_nb_samples, dst_sample_fmt, 0); - if (ret < 0) { - fprintf(stderr, "Could not allocate destination samples\n"); - goto end; - } - - t = 0; - do { - /* generate synthetic audio */ - fill_samples((double *)src_data[0], src_nb_samples, src_nb_channels, src_rate, &t); - - /* compute destination number of samples */ - dst_nb_samples = av_rescale_rnd(swr_get_delay(swr_ctx, src_rate) + - src_nb_samples, dst_rate, src_rate, AV_ROUND_UP); - if (dst_nb_samples > max_dst_nb_samples) { - av_freep(&dst_data[0]); - ret = av_samples_alloc(dst_data, &dst_linesize, dst_nb_channels, - dst_nb_samples, dst_sample_fmt, 1); - if (ret < 0) - break; - max_dst_nb_samples = dst_nb_samples; - } - - /* convert to destination format */ - ret = swr_convert(swr_ctx, dst_data, dst_nb_samples, (const uint8_t **)src_data, src_nb_samples); - if (ret < 0) { - fprintf(stderr, "Error while converting\n"); - goto end; - } - dst_bufsize = av_samples_get_buffer_size(&dst_linesize, dst_nb_channels, - ret, dst_sample_fmt, 1); - if (dst_bufsize < 0) { - fprintf(stderr, "Could not get sample buffer size\n"); - goto end; - } - printf("t:%f in:%d out:%d\n", t, src_nb_samples, ret); - fwrite(dst_data[0], 1, dst_bufsize, dst_file); - } while (t < 10); - - if ((ret = get_format_from_sample_fmt(&fmt, dst_sample_fmt)) < 0) - goto end; - av_channel_layout_describe(&dst_ch_layout, buf, sizeof(buf)); - fprintf(stderr, "Resampling succeeded. Play the output file with the command:\n" - "ffplay -f %s -channel_layout %s -channels %d -ar %d %s\n", - fmt, buf, dst_nb_channels, dst_rate, dst_filename); - -end: - fclose(dst_file); - - if (src_data) - av_freep(&src_data[0]); - av_freep(&src_data); - - if (dst_data) - av_freep(&dst_data[0]); - av_freep(&dst_data); - - swr_free(&swr_ctx); - return ret < 0; -} |