Function ff_dca_exss_parse

libavcodec/dca_exss.c:378–514

}

int ff_dca_exss_parse(DCAExssParser *s, const uint8_t *data, int size)
{
    int i, ret, offset, wide_hdr, header_size;

    if ((ret = init_get_bits8(&s->gb, data, size)) < 0)
        return ret;

    // Extension substream sync word
    skip_bits_long(&s->gb, 32);

    // User defined bits
    skip_bits(&s->gb, 8);

    // Extension substream index
    s->exss_index = get_bits(&s->gb, 2);

    // Flag indicating short or long header size
    wide_hdr = get_bits1(&s->gb);

    // Extension substream header length
    header_size = get_bits(&s->gb, 8 + 4 * wide_hdr) + 1;

    // Check CRC
    if (s->avctx && ff_dca_check_crc(s->avctx, &s->gb, 32 + 8, header_size * 8)) {
        av_log(s->avctx, AV_LOG_ERROR, "Invalid EXSS header checksum\n");
        return AVERROR_INVALIDDATA;
    }

    s->exss_size_nbits = 16 + 4 * wide_hdr;

    // Number of bytes of extension substream
    s->exss_size = get_bits(&s->gb, s->exss_size_nbits) + 1;
    if (s->exss_size > size) {
        if (s->avctx)
            av_log(s->avctx, AV_LOG_ERROR, "Packet too short for EXSS frame\n");
        return AVERROR_INVALIDDATA;
    }

    // Per stream static fields presence flag
    if (s->static_fields_present = get_bits1(&s->gb)) {
        int active_exss_mask[8];

        // Reference clock code
        skip_bits(&s->gb, 2);

        // Extension substream frame duration
        skip_bits(&s->gb, 3);

        // Timecode presence flag
        if (get_bits1(&s->gb))
            // Timecode data
            skip_bits_long(&s->gb, 36);

        // Number of defined audio presentations
        s->npresents = get_bits(&s->gb, 3) + 1;
        if (s->npresents > 1) {
            if (s->avctx)
                avpriv_request_sample(s->avctx, "%d audio presentations", s->npresents);