[FFmpeg-devel] [PATCH v2 2/2] avformat: add demuxer for Pro Pinball Series' Soundbanks

[Zane van Iperen]

On Wed, 18 Mar 2020 15:19:19 +0100
"Carl Eugen Hoyos" <ceffmpeg at gmail.com> wrote:
> 
> Any restrictions on track_count and sample_rate that can be used for
> auto-detection?
> 

I've done a preliminary probe function. How's this?

On all the files I tested, I received one of two values:
99 - For music (these have an extra condition I can test for)
87 - For everything else

static int pp_bnk_probe(const AVProbeData *p)
{
    PPBnkHeader hdr;
    uint32_t expected_sample_rate;
    int score;

    pp_bnk_parse_header(&hdr, p->buf);

    if (hdr.track_count == 0 || hdr.sample_rate == 0)
        return 0;

    score = 0;

    /* These limits are based on analysing the game files. */
    if (hdr.track_count <= 113)
        score += AVPROBE_SCORE_MAX / 4;

    if (hdr.sample_rate <= 44100)
        score += AVPROBE_SCORE_MAX / 4;

    if ((hdr.flags & ~PP_BNK_FLAG_MASK) == 0)
        score += AVPROBE_SCORE_MAX / 4;

    if ((hdr.flags & PP_BNK_FLAG_MUSIC) && hdr.track_count == 2)
        score += AVPROBE_SCORE_MAX / 8;

    /* Also check based on file extension, if we have it. */
    if (av_match_ext(p->filename, "5c"))
        expected_sample_rate = 5512;
    else if (av_match_ext(p->filename, "11c"))
        expected_sample_rate = 11025;
    else if (av_match_ext(p->filename, "22c"))
        expected_sample_rate = 22050;
    else if (av_match_ext(p->filename, "44c"))
        expected_sample_rate = 44100;
    else
        expected_sample_rate = 0;

    if (expected_sample_rate && hdr.sample_rate == expected_sample_rate)
        score += AVPROBE_SCORE_MAX / 8;

    return score;
}

Zane