enc->frame_size = fifo_bytes / (2 * enc->channels);
av_fifo_generic_read(ost->fifo, samples, fifo_bytes, NULL);
ret = avcodec_encode_audio(enc, bit_buffer, bit_buffer_size, samples);
enc->frame_size = fifo_bytes / (2 * enc->channels);
av_fifo_generic_read(ost->fifo, samples, fifo_bytes, NULL);
ret = avcodec_encode_audio(enc, bit_buffer, bit_buffer_size, samples);