avcodec/option_table: mark venc_params as a video decoder flag opt type

It's not meant for audio or subtitles, or for encoders of any kind.
Reviewed-by: mypopy@gmail.com <mypopy@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/options_table.h

@@ -81,7 +81,7 @@ static const AVOption avcodec_options[] = {
 {"export_side_data", "Export metadata as side data", OFFSET(export_side_data), AV_OPT_TYPE_FLAGS, {.i64 = DEFAULT}, 0, UINT_MAX, A|V|S|D|E, "export_side_data"},
 {"mvs", "export motion vectors through frame side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_EXPORT_DATA_MVS}, INT_MIN, INT_MAX, V|D, "export_side_data"},
 {"prft", "export Producer Reference Time through packet side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_EXPORT_DATA_PRFT}, INT_MIN, INT_MAX, A|V|S|E, "export_side_data"},
-{"venc_params", "export video encoding parameters through frame side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS}, INT_MIN, INT_MAX, A|V|S|E, "export_side_data"},
+{"venc_params", "export video encoding parameters through frame side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS}, INT_MIN, INT_MAX, V|D, "export_side_data"},
 {"time_base", NULL, OFFSET(time_base), AV_OPT_TYPE_RATIONAL, {.dbl = 0}, 0, INT_MAX},
 {"g", "set the group of picture (GOP) size", OFFSET(gop_size), AV_OPT_TYPE_INT, {.i64 = 12 }, INT_MIN, INT_MAX, V|E},
 {"ar", "set audio sampling rate (in Hz)", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX, A|D|E},