lavfi: add video buffer sink, and use it in avtools

Also add the public interface libavfilter/buffersink.h.

Based on a commit by Stefano Sabatini.

4 files changed, 163 insertions, 0 deletions

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index ae858397df..e786b6d2fe 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -4,6 +4,7 @@ FFLIBS-$(CONFIG_MOVIE_FILTER) += avformat avcodec
 
 HEADERS = avfilter.h                                                    \
           avfiltergraph.h                                               \
+          buffersink.h                                                  \
           buffersrc.h                                                   \
           version.h                                                     \
           vsrc_buffer.h                                                 \
@@ -11,6 +12,7 @@ HEADERS = avfilter.h                                                    \
 OBJS = allfilters.o                                                     \
        avfilter.o                                                       \
        avfiltergraph.o                                                  \
+       buffersink.o                                                     \
        defaults.o                                                       \
        drawutils.o                                                      \
        formats.o                                                        \
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 198e152cb0..f887002b66 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -95,6 +95,10 @@ void avfilter_register_all(void)
         avfilter_register(&avfilter_vsrc_buffer);
     }
     {
+        extern AVFilter avfilter_vsink_buffer;
+        avfilter_register(&avfilter_vsink_buffer);
+    }
+    {
         extern AVFilter avfilter_vf_scale;
         avfilter_register(&avfilter_vf_scale);
     }
diff --git a/libavfilter/buffersink.c b/libavfilter/buffersink.c
new file mode 100644
index 0000000000..e4cbe3be42
--- /dev/null
+++ b/libavfilter/buffersink.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * buffer sink
+ */
+
+#include "libavutil/fifo.h"
+
+#include "avfilter.h"
+#include "buffersink.h"
+
+typedef struct {
+    AVFifoBuffer *fifo;          ///< FIFO buffer of video frame references
+} BufferSinkContext;
+
+#define FIFO_INIT_SIZE 8
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    BufferSinkContext *sink = ctx->priv;
+
+    while (sink->fifo && av_fifo_size(sink->fifo)) {
+        AVFilterBufferRef *buf;
+        av_fifo_generic_read(sink->fifo, &buf, sizeof(buf), NULL);
+        avfilter_unref_buffer(buf);
+    }
+    av_fifo_free(sink->fifo);
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    BufferSinkContext *sink = ctx->priv;
+
+    if (!(sink->fifo = av_fifo_alloc(FIFO_INIT_SIZE*sizeof(AVFilterBufferRef*)))) {
+        av_log(ctx, AV_LOG_ERROR, "Failed to allocate fifo\n");
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+static void end_frame(AVFilterLink *link)
+{
+    AVFilterContext   *ctx = link->dst;
+    BufferSinkContext *sink = ctx->priv;
+
+    if (av_fifo_space(sink->fifo) < sizeof(AVFilterBufferRef *) &&
+        (av_fifo_realloc2(sink->fifo, av_fifo_size(sink->fifo) * 2) < 0)) {
+            av_log(ctx, AV_LOG_ERROR, "Error reallocating the FIFO.\n");
+            return;
+    }
+
+    av_fifo_generic_write(sink->fifo, &link->cur_buf, sizeof(link->cur_buf), NULL);
+    link->cur_buf = NULL;
+}
+
+int av_buffersink_read(AVFilterContext *ctx, AVFilterBufferRef **buf)
+{
+    BufferSinkContext *sink = ctx->priv;
+    AVFilterLink      *link = ctx->inputs[0];
+    int ret;
+
+    if (!buf) {
+        if (av_fifo_size(sink->fifo))
+            return av_fifo_size(sink->fifo)/sizeof(*buf);
+        else
+            return avfilter_poll_frame(ctx->inputs[0]);
+    }
+
+    if (!av_fifo_size(sink->fifo) &&
+        (ret = avfilter_request_frame(link)) < 0)
+        return ret;
+
+    if (!av_fifo_size(sink->fifo))
+        return AVERROR(EINVAL);
+
+    av_fifo_generic_read(sink->fifo, buf, sizeof(*buf), NULL);
+
+    return 0;
+}
+
+AVFilter avfilter_vsink_buffer = {
+    .name      = "buffersink",
+    .description = NULL_IF_CONFIG_SMALL("Buffer video frames, and make them available to the end of the filter graph."),
+    .priv_size = sizeof(BufferSinkContext),
+    .init      = init,
+    .uninit    = uninit,
+
+    .inputs    = (AVFilterPad[]) {{ .name          = "default",
+                                    .type          = AVMEDIA_TYPE_VIDEO,
+                                    .end_frame     = end_frame,
+                                    .min_perms     = AV_PERM_READ, },
+                                  { .name = NULL }},
+    .outputs   = (AVFilterPad[]) {{ .name = NULL }},
+};
diff --git a/libavfilter/buffersink.h b/libavfilter/buffersink.h
new file mode 100644
index 0000000000..e579b9ad03
--- /dev/null
+++ b/libavfilter/buffersink.h
@@ -0,0 +1,43 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFILTER_BUFFERSINK_H
+#define AVFILTER_BUFFERSINK_H
+
+/**
+ * @file
+ * memory buffer sink API
+ */
+
+#include "avfilter.h"
+
+/**
+ * Get a buffer with filtered data from sink and put it in buf.
+ *
+ * @param sink pointer to a context of a buffersink AVFilter.
+ * @param buf pointer to the buffer will be written here if buf is non-NULL. buf
+ *            must be freed by the caller using avfilter_unref_buffer().
+ *            Buf may also be NULL to query whether a buffer is ready to be
+ *            output.
+ *
+ * @return >= 0 in case of success, a negative AVERROR code in case of
+ *         failure.
+ */
+int av_buffersink_read(AVFilterContext *sink, AVFilterBufferRef **buf);
+
+#endif /* AVFILTER_BUFFERSINK_H */