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rtpengine/lib/resample.c

106 lines
2.9 KiB

#include "resample.h"
#include <glib.h>
#include <libavfilter/avfilter.h>
#include <libavfilter/buffersrc.h>
#include <libavfilter/buffersink.h>
#include <libavutil/channel_layout.h>
#include <libavutil/mathematics.h>
#include <inttypes.h>
#include <libswresample/swresample.h>
#include <libavutil/opt.h>
#include <libavutil/frame.h>
#include "log.h"
#include "codeclib.h"
#include "fix_frame_channel_layout.h"
AVFrame *resample_frame(resample_t *resample, AVFrame *frame, const format_t *to_format) {
const char *err;
int errcode = 0;
CH_LAYOUT_T to_channel_layout;
DEF_CH_LAYOUT(&to_channel_layout, to_format->channels);
fix_frame_channel_layout(frame);
if (frame->format != to_format->format)
goto resample;
if (frame->sample_rate != to_format->clockrate)
goto resample;
if (!CH_LAYOUT_EQ(frame->CH_LAYOUT, to_channel_layout))
goto resample;
return frame;
resample:
if (G_UNLIKELY(!resample->swresample)) {
SWR_ALLOC_SET_OPTS(&resample->swresample,
to_channel_layout,
to_format->format,
to_format->clockrate,
frame->CH_LAYOUT,
frame->format,
frame->sample_rate,
0, NULL);
err = "failed to alloc resample context";
if (!resample->swresample)
goto err;
if (resample->no_filter)
av_opt_set_int(resample->swresample, "filter_size", 0, AV_OPT_SEARCH_CHILDREN);
err = "failed to init resample context";
if ((errcode = swr_init(resample->swresample)) < 0)
goto err;
}
// get a large enough buffer for resampled audio - this should be enough so we don't
// have to loop
int dst_samples = av_rescale_rnd(swr_get_delay(resample->swresample, to_format->clockrate)
+ frame->nb_samples,
to_format->clockrate, frame->sample_rate, AV_ROUND_UP);
AVFrame *swr_frame = av_frame_alloc();
err = "failed to alloc resampling frame";
if (!swr_frame)
goto err;
av_frame_copy_props(swr_frame, frame);
swr_frame->format = to_format->format;
swr_frame->CH_LAYOUT = to_channel_layout;
swr_frame->nb_samples = dst_samples;
swr_frame->sample_rate = to_format->clockrate;
err = "failed to get resample buffers";
if ((errcode = av_frame_get_buffer(swr_frame, 0)) < 0)
goto err;
int ret_samples = swr_convert(resample->swresample, swr_frame->extended_data,
dst_samples,
(const uint8_t **) frame->extended_data,
frame->nb_samples);
err = "failed to resample audio";
if ((errcode = ret_samples) < 0)
goto err;
swr_frame->nb_samples = ret_samples;
swr_frame->pts = av_rescale(frame->pts, to_format->clockrate, frame->sample_rate);
swr_frame->linesize[0] = av_get_bytes_per_sample(swr_frame->format) * ret_samples;
return swr_frame;
err:
if (errcode)
ilog(LOG_ERR | LOG_FLAG_LIMIT, "Error resampling: %s (%s)", err, av_error(errcode));
else
ilog(LOG_ERR | LOG_FLAG_LIMIT, "Error resampling: %s", err);
resample_shutdown(resample);
return NULL;
}
void resample_shutdown(resample_t *resample) {
swr_free(&resample->swresample);
}