{"context", "context model", OFFSET(context_model), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, V|E},
{"slice_flags", NULL, OFFSET(slice_flags), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
{"xvmc_acceleration", NULL, OFFSET(xvmc_acceleration), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
-{"mbd", "macroblock decision algorithm (high quality mode)", OFFSET(mb_decision), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, V|E, "mbd"},
+{"mbd", "macroblock decision algorithm (high quality mode)", OFFSET(mb_decision), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, 2, V|E, "mbd"},
{"simple", "use mbcmp (default)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MB_DECISION_SIMPLE }, INT_MIN, INT_MAX, V|E, "mbd"},
{"bits", "use fewest bits", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MB_DECISION_BITS }, INT_MIN, INT_MAX, V|E, "mbd"},
{"rd", "use best rate distortion", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MB_DECISION_RD }, INT_MIN, INT_MAX, V|E, "mbd"},