ffplay: add support for libswresample options

Signed-off-by: Marton Balint <cus@passwd.hu>

ffplay.c

@@ -1833,6 +1833,8 @@ static int configure_audio_filters(VideoState *is, const char *afilters, int for
     int64_t channel_layouts[2] = { 0, -1 };
     int channels[2] = { 0, -1 };
     AVFilterContext *filt_asrc = NULL, *filt_asink = NULL;
+    char aresample_swr_opts[512] = "";
+    AVDictionaryEntry *e = NULL;
     char asrc_args[256];
     int ret;
 
@@ -1840,6 +1842,12 @@ static int configure_audio_filters(VideoState *is, const char *afilters, int for
     if (!(is->agraph = avfilter_graph_alloc()))
         return AVERROR(ENOMEM);
 
+    while ((e = av_dict_get(swr_opts, "", e, AV_DICT_IGNORE_SUFFIX)))
+        av_strlcatf(aresample_swr_opts, sizeof(aresample_swr_opts), "%s=%s:", e->key, e->value);
+    if (strlen(aresample_swr_opts))
+        aresample_swr_opts[strlen(aresample_swr_opts)-1] = '\0';
+    av_opt_set(is->agraph, "aresample_swr_opts", aresample_swr_opts, 0);
+
     ret = snprintf(asrc_args, sizeof(asrc_args),
                    "sample_rate=%d:sample_fmt=%s:channels=%d:time_base=%d/%d",
                    is->audio_filter_src.freq, av_get_sample_fmt_name(is->audio_filter_src.fmt),