proc av_add_stable(ts_tb: AVRational; ts: int64; inc_tb: AVRational; inc: int64): int64 {.
    importc, cdecl, ...raises: [], tags: [], forbids: [].}

proc av_compare_mod(a, b, mod: uint64): int64 {.importc, cdecl, ...raises: [],
    tags: [], forbids: [].}

proc av_compare_ts(ts_a: int64; tb_a: AVRational; ts_b: int64; tb_b: AVRational): cint {.
    importc, cdecl, ...raises: [], tags: [], forbids: [].}

proc av_gcd(a, b: int64): int64 {.importc, cdecl, ...raises: [], tags: [],
                                  forbids: [].}

proc av_rescale(a, b, c: int64): int64 {.importc, cdecl, ...raises: [], tags: [],
    forbids: [].}

proc av_rescale_delta(in_tb: AVRational; in_ts: int64; fs_tb: AVRational;
                      duration: cint; last: ptr int64; out_tb: AVRational): int64 {.
    importc, cdecl, ...raises: [], tags: [], forbids: [].}

proc av_rescale_q(a: int64; bq, cq: AVRational): int64 {.importc, cdecl,
    ...raises: [], tags: [], forbids: [].}

proc av_rescale_q_rnd(a: int64; bq, cq: AVRational; rnd: AVRounding): int64 {.
    importc, cdecl, ...raises: [], tags: [], forbids: [].}

proc av_rescale_rnd(a, b, c: int64; rnd: AVRounding): int64 {.importc, cdecl,
    ...raises: [], tags: [], forbids: [].}