Am Do., 3. Sept. 2020 um 01:17 Uhr schrieb <liush...@aosc.io>:
> +static int probe(const AVProbeData *p)
> +{
> + if (AV_RL32(p->buf) == MKTAG('M', 'A', 'D', 'P') &&
> + AV_RL16(p->buf + 4) <= 0xff)
> + return AVPROBE_SCORE_MAX / 3 * 2;
> + return 0;
> +}
> + if (version <= 4) {
> + // version <= 4 needs to use the file size to calculate the offsets
> + if (file_size < 0) {
> + return AVERROR(EIO);
> + }
> + if (file_size - data_size > UINT32_MAX)
> + return AVERROR_INVALIDDATA;
> + m->data_start = file_size - data_size;
> + if (version <= 3) {
> + nb_metadata = 0;
> + // header_size is not available or incorrect in older versions
> + header_size = m->data_start;
> + }
> + } else if (version == 5) {
> + // read data_start location from the header
> + if (0x30 * par->channels + 0x4 > header_size)
> + return AVERROR_INVALIDDATA;
> + data_offset = header_size - 0x30 * par->channels - 0x4;
> + if ((ret_size = avio_seek(s->pb, data_offset, SEEK_SET)) < 0)
> + return ret_size;
> + m->data_start = avio_rl32(s->pb);
> + // check if the metadata is reasonable
> + if (file_size > 0 && (int64_t)m->data_start + data_size > file_size)
> {
> + // the header is broken beyond repair
> + if ((int64_t)header_size + data_size > file_size) {
> + av_log(s, AV_LOG_ERROR,
> + "MCA metadata corrupted, unable to determine the data
> offset.\n");
> + return AVERROR_INVALIDDATA;
> + }
> + // recover the data_start information from the data size
> + av_log(s, AV_LOG_WARNING,
> + "Incorrect header size found in metadata, "
> + "header size approximated from the data size\n");
> + if (file_size - data_offset > UINT32_MAX)
> + return AVERROR_INVALIDDATA;
> + m->data_start = file_size - data_size;
> + }
> + } else {
> + avpriv_request_sample(s, "version %d", version);
> + return AVERROR_PATCHWELCOME;
> + }
It seems to me that you are much stricter checking the version
when reading the header information than when probing the file
but if there is a difference, the probing should be stricter.
Please check in the probe function if version <= 5.
Carl Eugen
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