Enable audio transmission

This commit is contained in:
dijunkun
2023-11-29 22:04:53 -08:00
parent 733434f9b3
commit 4a65a59803
12 changed files with 1520 additions and 271 deletions

View File

@@ -0,0 +1,232 @@
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavdevice/avdevice.h>
#include <libavfilter/avfilter.h>
#include <libavformat/avformat.h>
#include <libavutil/channel_layout.h>
#include <libavutil/imgutils.h>
#include <libavutil/opt.h>
#include <libavutil/samplefmt.h>
#include <libswresample/swresample.h>
#include <libswscale/swscale.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. <20><><EFBFBD><EFBFBD>ģʽ<C4A3><CABD>
*/
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) {
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
int64_t src_ch_layout = AV_CH_LAYOUT_MONO;
int src_rate = 44100;
enum AVSampleFormat src_sample_fmt = AV_SAMPLE_FMT_DBL;
int src_nb_channels = 0;
uint8_t **src_data = NULL; // <20><><EFBFBD><EFBFBD>ָ<EFBFBD><D6B8>
int src_linesize;
int src_nb_samples = 1024;
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
int64_t dst_ch_layout = AV_CH_LAYOUT_STEREO;
int dst_rate = 48000;
enum AVSampleFormat dst_sample_fmt = AV_SAMPLE_FMT_S16;
int dst_nb_channels = 0;
uint8_t **dst_data = NULL; // <20><><EFBFBD><EFBFBD>ָ<EFBFBD><D6B8>
int dst_linesize;
int dst_nb_samples;
int max_dst_nb_samples;
// <20><><EFBFBD><EFBFBD><EFBFBD>ļ<EFBFBD>
const char *dst_filename = NULL; // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>pcm<63><6D><EFBFBD><EFBFBD><EFBFBD>أ<EFBFBD>Ȼ<EFBFBD>󲥷<EFBFBD><F3B2A5B7><EFBFBD>֤
FILE *dst_file;
int dst_bufsize;
const char *fmt;
// <20>ز<EFBFBD><D8B2><EFBFBD>ʵ<EFBFBD><CAB5>
struct SwrContext *swr_ctx;
double t;
int ret;
dst_filename = "res.pcm";
dst_file = fopen(dst_filename, "wb");
if (!dst_file) {
fprintf(stderr, "Could not open destination file %s\n", dst_filename);
exit(1);
}
// <20><><EFBFBD><EFBFBD><EFBFBD>ز<EFBFBD><D8B2><EFBFBD><EFBFBD><EFBFBD>
/* create resampler context */
swr_ctx = swr_alloc();
if (!swr_ctx) {
fprintf(stderr, "Could not allocate resampler context\n");
ret = AVERROR(ENOMEM);
goto end;
}
// <20><><EFBFBD><EFBFBD><EFBFBD>ز<EFBFBD><D8B2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
/* set options */
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
av_opt_set_int(swr_ctx, "in_channel_layout", 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);
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
av_opt_set_int(swr_ctx, "out_channel_layout", 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);
// <20><>ʼ<EFBFBD><CABC><EFBFBD>ز<EFBFBD><D8B2><EFBFBD>
/* 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 */
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Դ<EFBFBD><D4B4>ͨ<EFBFBD><CDA8><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
src_nb_channels = av_get_channel_layout_nb_channels(src_ch_layout);
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Դ<EFBFBD><D4B4><EFBFBD><EFBFBD><EFBFBD>ڴ<EFBFBD><DAB4>ռ<EFBFBD>
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 */
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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 = av_get_channel_layout_nb_channels(dst_ch_layout);
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڴ<EFBFBD>
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 */
// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Դ
fill_samples((double *)src_data[0], src_nb_samples, src_nb_channels,
src_rate, &t);
/* compute destination number of samples */
int64_t delay = swr_get_delay(swr_ctx, src_rate);
dst_nb_samples =
av_rescale_rnd(delay + 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;
}
// int fifo_size = swr_get_out_samples(swr_ctx,src_nb_samples);
// printf("fifo_size:%d\n", fifo_size);
// if(fifo_size < 1024)
// continue;
/* convert to destination format */
// ret = swr_convert(swr_ctx, dst_data, dst_nb_samples, (const
// uint8_t **)src_data, src_nb_samples);
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);
ret = swr_convert(swr_ctx, dst_data, dst_nb_samples, NULL, 0);
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("flush in:%d out:%d\n", 0, ret);
fwrite(dst_data[0], 1, dst_bufsize, dst_file);
if ((ret = get_format_from_sample_fmt(&fmt, dst_sample_fmt)) < 0) goto end;
fprintf(stderr,
"Resampling succeeded. Play the output file with the command:\n"
"ffplay -f %s -channel_layout %" PRId64 " -channels %d -ar %d %s\n",
fmt, dst_ch_layout, 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;
}