Function opus_encode_frame

libavcodec/opus/enc.c:547–615

}

static int opus_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                             const AVFrame *frame, int *got_packet_ptr)
{
    OpusEncContext *s = avctx->priv_data;
    int ret, frame_size, discard_padding, alloc_size = 0;

    if (frame) { /* Add new frame to queue */
        if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)
            return ret;
        ff_bufqueue_add(avctx, &s->bufqueue, av_frame_clone(frame));
    } else {
        ff_opus_psy_signal_eof(&s->psyctx);
        if (!s->afq.remaining_samples || !avctx->frame_num)
            return 0; /* We've been flushed and there's nothing left to encode */
    }

    /* Run the psychoacoustic system */
    if (ff_opus_psy_process(&s->psyctx, &s->packet))
        return 0;

    frame_size = OPUS_BLOCK_SIZE(s->packet.framesize);

    if (!frame) {
        /* This can go negative, that's not a problem, we only pad if positive */
        int pad_empty = s->packet.frames*(frame_size/s->avctx->frame_size) - s->bufqueue.available + 1;
        /* Pad with empty 2.5 ms frames to whatever framesize was decided,
         * this should only happen at the very last flush frame. The frames
         * allocated here will be freed (because they have no other references)
         * after they get used by celt_frame_setup_input() */
        for (int i = 0; i < pad_empty; i++) {
            AVFrame *empty = spawn_empty_frame(s);
            if (!empty)
                return AVERROR(ENOMEM);
            ff_bufqueue_add(avctx, &s->bufqueue, empty);
        }
    }

    for (int i = 0; i < s->packet.frames; i++) {
        celt_encode_frame(s, &s->rc[i], &s->frame[i], i);
        alloc_size += s->frame[i].framebits >> 3;
    }

    /* Worst case toc + the frame lengths if needed */
    alloc_size += 2 + s->packet.frames*2;

    if ((ret = ff_alloc_packet(avctx, avpkt, alloc_size)) < 0)
        return ret;

    /* Assemble packet */
    opus_packet_assembler(s, avpkt);

    /* Update the psychoacoustic system */
    ff_opus_psy_postencode_update(&s->psyctx, s->frame);

    /* Remove samples from queue and skip if needed */
    ff_af_queue_remove(&s->afq, s->packet.frames*frame_size, &avpkt->pts, &avpkt->duration);

    discard_padding = s->packet.frames*frame_size - ff_samples_from_time_base(avctx, avpkt->duration);