Function decode

libavcodec/pgssubdec.c:592–677

}

static int decode(AVCodecContext *avctx, AVSubtitle *sub,
                  int *got_sub_ptr, const AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;

    const uint8_t *buf_end;
    uint8_t       segment_type;
    int           segment_length;
    int i, ret;

    ff_dlog(avctx, "PGS sub packet:\n");

    for (i = 0; i < buf_size; i++) {
        ff_dlog(avctx, "%02x ", buf[i]);
        if (i % 16 == 15)
            ff_dlog(avctx, "\n");
    }

    if (i & 15)
        ff_dlog(avctx, "\n");

    *got_sub_ptr = 0;

    /* Ensure that we have received at a least a segment code and segment length */
    if (buf_size < 3)
        return -1;

    buf_end = buf + buf_size;

    /* Step through buffer to identify segments */
    while (buf < buf_end) {
        segment_type   = bytestream_get_byte(&buf);
        segment_length = bytestream_get_be16(&buf);

        ff_dlog(avctx, "Segment Length %d, Segment Type %x\n", segment_length, segment_type);

        if (segment_type != DISPLAY_SEGMENT && segment_length > buf_end - buf)
            break;

        ret = 0;
        switch (segment_type) {
        case PALETTE_SEGMENT:
            ret = parse_palette_segment(avctx, buf, segment_length);
            break;
        case OBJECT_SEGMENT:
            ret = parse_object_segment(avctx, buf, segment_length);
            break;
        case PRESENTATION_SEGMENT:
            ret = parse_presentation_segment(avctx, buf, segment_length, sub->pts);
            break;
        case WINDOW_SEGMENT:
            /*
             * Window Segment Structure (No new information provided):
             *     2 bytes: Unknown,
             *     2 bytes: X position of subtitle,
             *     2 bytes: Y position of subtitle,
             *     2 bytes: Width of subtitle,