Function encode_superframe

libavcodec/wmaenc.c:378–436

}

static int encode_superframe(AVCodecContext *avctx, AVPacket *avpkt,
                             const AVFrame *frame, int *got_packet_ptr)
{
    WMACodecContext *s = avctx->priv_data;
    int i, total_gain, ret, error;

    s->block_len_bits = s->frame_len_bits; // required by non variable block len
    s->block_len      = 1 << s->block_len_bits;

    ret = apply_window_and_mdct(avctx, frame);

    if (ret < 0)
        return ret;

    if (s->ms_stereo) {
        float a, b;
        int i;

        for (i = 0; i < s->block_len; i++) {
            a              = s->coefs[0][i] * 0.5;
            b              = s->coefs[1][i] * 0.5;
            s->coefs[0][i] = a + b;
            s->coefs[1][i] = a - b;
        }
    }

    if ((ret = ff_alloc_packet(avctx, avpkt, 2 * MAX_CODED_SUPERFRAME_SIZE)) < 0)
        return ret;

    total_gain = 128;
    for (i = 64; i; i >>= 1) {
        error = encode_frame(s, s->coefs, avpkt->data, avpkt->size,
                                 total_gain - i);
        if (error <= 0)
            total_gain -= i;
    }

    while(total_gain <= 128 && error > 0)
        error = encode_frame(s, s->coefs, avpkt->data, avpkt->size, total_gain++);
    if (error > 0) {
        av_log(avctx, AV_LOG_ERROR, "Invalid input data or requested bitrate too low, cannot encode\n");
        return AVERROR(EINVAL);
    }
    av_assert0((put_bits_count(&s->pb) & 7) == 0);
    i = avctx->block_align - put_bytes_count(&s->pb, 0);
    av_assert0(i>=0);
    while(i--)
        put_bits(&s->pb, 8, 'N');

    flush_put_bits(&s->pb);
    av_assert0(put_bytes_output(&s->pb) == avctx->block_align);

    if (frame->pts != AV_NOPTS_VALUE)
        avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding);

    avpkt->size     = avctx->block_align;
    *got_packet_ptr = 1;
    return 0;