+ { "enc_time_base", HAS_ARG | OPT_STRING | OPT_EXPERT | OPT_SPEC | OPT_OUTPUT, { .off = OFFSET(enc_time_bases) },
+ "set the desired time base for the encoder (1:24, 1:48000 or 0.04166, 2.0833e-5). "
+ "two special values are defined - "
+ "0 = use frame rate (video) or sample rate (audio),"
+ "-1 = match source time base", "ratio" },