diff --git a/libavformat/cdxl.c b/libavformat/cdxl.c index b65011a072..fb2d2a40c3 100644 --- a/libavformat/cdxl.c +++ b/libavformat/cdxl.c @@ -38,6 +38,48 @@ typedef struct CDXLDemuxContext { int audio_stream_index; } CDXLDemuxContext; +static int cdxl_read_probe(AVProbeData *p) +{ + int score = AVPROBE_SCORE_MAX / 2 + 10; + + if (p->buf_size < CDXL_HEADER_SIZE) + return 0; + + /* reserved bytes should always be set to 0 */ + if (AV_RN64(&p->buf[24]) || AV_RN16(&p->buf[10])) + return 0; + + /* check type */ + if (p->buf[0] != 1) + return 0; + + /* check palette size */ + if (AV_RB16(&p->buf[20]) > 512) + return 0; + + /* check number of planes */ + if (p->buf[18] || !p->buf[19]) + return 0; + + /* check widh and height */ + if (!AV_RN16(&p->buf[14]) || !AV_RN16(&p->buf[16])) + return 0; + + /* chunk size */ + if (AV_RB32(&p->buf[2]) < AV_RB16(&p->buf[22]) + AV_RB16(&p->buf[20]) + CDXL_HEADER_SIZE) + return 0; + + /* previous chunk size */ + if (AV_RN32(&p->buf[6])) + score /= 2; + + /* current frame number, usually starts from 1 */ + if (AV_RB16(&p->buf[12]) != 1) + score /= 2; + + return score; +} + static int cdxl_read_header(AVFormatContext *s) { CDXLDemuxContext *cdxl = s->priv_data; @@ -173,6 +215,7 @@ AVInputFormat ff_cdxl_demuxer = { .name = "cdxl", .long_name = NULL_IF_CONFIG_SMALL("Commodore CDXL video"), .priv_data_size = sizeof(CDXLDemuxContext), + .read_probe = cdxl_read_probe, .read_header = cdxl_read_header, .read_packet = cdxl_read_packet, .extensions = "cdxl,xl",