avfilter/vf_waveform: add input option

For finer control of selected formats for filtering.

doc/filters.texi

@@ -24950,6 +24950,12 @@ Set sample aspect ration to 1/1.
 Set sample aspect ratio to match input size of video
 @end table
 Default is @samp{none}.
+
+@item input
+Set input formats for filter to pick from.
+Can be @samp{all}, for selecting from all available formats,
+or @samp{first}, for selecting first available format.
+Default is @samp{first}.
 @end table
 
 @section weave, doubleweave

libavfilter/vf_waveform.c

@@ -120,6 +120,7 @@ typedef struct WaveformContext {
     float          ftint[2];
     int            tint[2];
     int            fitmode;
+    int            input;
 
     int (*waveform_slice)(AVFilterContext *ctx, void *arg,
                           int jobnr, int nb_jobs);
@@ -196,6 +197,9 @@ static const AVOption waveform_options[] = {
     { "fm", "set fit mode", OFFSET(fitmode), AV_OPT_TYPE_INT, {.i64=0}, 0, NB_FITMODES-1, FLAGS, "fitmode" },
         { "none", NULL, 0, AV_OPT_TYPE_CONST, {.i64=FM_NONE}, 0, 0, FLAGS, "fitmode" },
         { "size", NULL, 0, AV_OPT_TYPE_CONST, {.i64=FM_SIZE}, 0, 0, FLAGS, "fitmode" },
+    { "input", "set input formats selection", OFFSET(input), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS, "input" },
+        { "all", "try to select from all available formats", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "input" },
+        { "first", "pick first available format", 0, AV_OPT_TYPE_CONST, {.i64=1},  0, 0, FLAGS, "input" },
     { NULL }
 };
 
@@ -356,7 +360,7 @@ static int query_formats(AVFilterContext *ctx)
     depth2 = desc2->comp[0].depth;
     if (ncomp != ncomp2 || depth != depth2)
         return AVERROR(EAGAIN);
-    for (i = 1; i < avff->nb_formats; i++) {
+    for (i = 1; i < avff->nb_formats && !s->input; i++) {
         desc = av_pix_fmt_desc_get(avff->formats[i]);
         if (rgb != (desc->flags & AV_PIX_FMT_FLAG_RGB) ||
             depth != desc->comp[0].depth)