audio_frame->sample_rate = OUTPUT_FREQUENCY;
if (av_samples_alloc(audio_frame->data, nullptr, 2, num_samples, ctx->sample_fmt, 0) < 0) {
audio_frame->sample_rate = OUTPUT_FREQUENCY;
if (av_samples_alloc(audio_frame->data, nullptr, 2, num_samples, ctx->sample_fmt, 0) < 0) {