avfilter/internal: Combine get_(audio|video)_buffer into union

These fields are mutually exclusive, so putting them in a union
is possible and makes AVFilterPad smaller.
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/audio.c

@@ -88,8 +88,8 @@ AVFrame *ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
 {
     AVFrame *ret = NULL;
 
-    if (link->dstpad->get_audio_buffer)
-        ret = link->dstpad->get_audio_buffer(link, nb_samples);
+    if (link->dstpad->get_buffer.audio)
+        ret = link->dstpad->get_buffer.audio(link, nb_samples);
 
     if (!ret)
         ret = ff_default_get_audio_buffer(link, nb_samples);

libavfilter/avf_concat.c

@@ -313,9 +313,11 @@ static av_cold int init(AVFilterContext *ctx)
             for (str = 0; str < cat->nb_streams[type]; str++) {
                 AVFilterPad pad = {
                     .type             = type,
-                    .get_video_buffer = get_video_buffer,
-                    .get_audio_buffer = get_audio_buffer,
                 };
+                if (type == AVMEDIA_TYPE_VIDEO)
+                    pad.get_buffer.video = get_video_buffer;
+                else
+                    pad.get_buffer.audio = get_audio_buffer;
                 pad.name = av_asprintf("in%d:%c%d", seg, "va"[type], str);
                 if ((ret = ff_insert_inpad(ctx, ctx->nb_inputs, &pad)) < 0) {
                     av_freep(&pad.name);

libavfilter/f_interleave.c

@@ -167,9 +167,9 @@ static av_cold int init(AVFilterContext *ctx)
 
         switch (outpad->type) {
         case AVMEDIA_TYPE_VIDEO:
-            inpad.get_video_buffer = ff_null_get_video_buffer; break;
+            inpad.get_buffer.video = ff_null_get_video_buffer; break;
         case AVMEDIA_TYPE_AUDIO:
-            inpad.get_audio_buffer = ff_null_get_audio_buffer; break;
+            inpad.get_buffer.audio = ff_null_get_audio_buffer; break;
         default:
             av_assert0(0);
         }

libavfilter/internal.h

@@ -61,20 +61,18 @@ struct AVFilterPad {
     enum AVMediaType type;
 
     /**
-     * Callback function to get a video buffer. If NULL, the filter system will
-     * use ff_default_get_video_buffer().
+     * Callback functions to get a video/audio buffers. If NULL,
+     * the filter system will use ff_default_get_video_buffer() for video
+     * and ff_default_get_audio_buffer() for audio.
      *
-     * Input video pads only.
-     */
-    AVFrame *(*get_video_buffer)(AVFilterLink *link, int w, int h);
-
-    /**
-     * Callback function to get an audio buffer. If NULL, the filter system will
-     * use ff_default_get_audio_buffer().
+     * The state of the union is determined by type.
      *
-     * Input audio pads only.
+     * Input pads only.
      */
-    AVFrame *(*get_audio_buffer)(AVFilterLink *link, int nb_samples);
+    union {
+        AVFrame *(*video)(AVFilterLink *link, int w, int h);
+        AVFrame *(*audio)(AVFilterLink *link, int nb_samples);
+    } get_buffer;
 
     /**
      * Filtering callback. This is where a filter receives a frame with

libavfilter/vf_format.c

@@ -149,7 +149,7 @@ static const AVFilterPad avfilter_vf_format_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = ff_null_get_video_buffer,
+        .get_buffer.video = ff_null_get_video_buffer,
     },
     { NULL }
 };
@@ -188,7 +188,7 @@ static const AVFilterPad avfilter_vf_noformat_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = ff_null_get_video_buffer,
+        .get_buffer.video = ff_null_get_video_buffer,
     },
     { NULL }
 };

libavfilter/vf_hwmap.c

@@ -404,7 +404,7 @@ static const AVFilterPad hwmap_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = hwmap_get_buffer,
+        .get_buffer.video = hwmap_get_buffer,
         .filter_frame     = hwmap_filter_frame,
     },
     { NULL }

libavfilter/vf_pad.c

@@ -438,7 +438,7 @@ static const AVFilterPad avfilter_vf_pad_inputs[] = {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
         .config_props     = config_input,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .filter_frame     = filter_frame,
     },
     { NULL }

libavfilter/vf_scale_cuda.c

@@ -623,7 +623,7 @@ static const AVFilterPad cudascale_inputs[] = {
         .name        = "default",
         .type        = AVMEDIA_TYPE_VIDEO,
         .filter_frame = cudascale_filter_frame,
-        .get_video_buffer = cudascale_get_video_buffer,
+        .get_buffer.video = cudascale_get_video_buffer,
     },
     { NULL }
 };

libavfilter/vf_swapuv.c

@@ -97,7 +97,7 @@ static const AVFilterPad swapuv_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .filter_frame     = filter_frame,
     },
     { NULL }

libavfilter/vf_transpose.c

@@ -383,7 +383,7 @@ static const AVFilterPad avfilter_vf_transpose_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .filter_frame = filter_frame,
     },
     { NULL }

libavfilter/vf_transpose_opencl.c

@@ -256,7 +256,7 @@ static const AVFilterPad transpose_opencl_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .filter_frame = &transpose_opencl_filter_frame,
         .config_props = &ff_opencl_filter_config_input,
     },

libavfilter/vf_transpose_vaapi.c

@@ -257,7 +257,7 @@ static const AVFilterPad transpose_vaapi_inputs[] = {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = &transpose_vaapi_filter_frame,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .config_props = &ff_vaapi_vpp_config_input,
     },
     { NULL }

libavfilter/vf_vflip.c

@@ -129,7 +129,7 @@ static const AVFilterPad avfilter_vf_vflip_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .filter_frame     = filter_frame,
         .config_props     = config_input,
     },

libavfilter/vf_xfade_opencl.c

@@ -402,13 +402,13 @@ static const AVFilterPad xfade_opencl_inputs[] = {
     {
         .name             = "main",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .config_props     = &ff_opencl_filter_config_input,
     },
     {
         .name             = "xfade",
         .type             = AVMEDIA_TYPE_VIDEO,
-        .get_video_buffer = get_video_buffer,
+        .get_buffer.video = get_video_buffer,
         .config_props     = &ff_opencl_filter_config_input,
     },
     { NULL }

libavfilter/video.c

@@ -101,8 +101,8 @@ AVFrame *ff_get_video_buffer(AVFilterLink *link, int w, int h)
 
     FF_TPRINTF_START(NULL, get_video_buffer); ff_tlog_link(NULL, link, 0);
 
-    if (link->dstpad->get_video_buffer)
-        ret = link->dstpad->get_video_buffer(link, w, h);
+    if (link->dstpad->get_buffer.video)
+        ret = link->dstpad->get_buffer.video(link, w, h);
 
     if (!ret)
         ret = ff_default_get_video_buffer(link, w, h);