Add "Memory buffer source filter" from SOC.

This is needed by the current SOC-ffmpeg.c code.

Originally committed as revision 23039 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/vsrc_buffer.c

+/*
+ * Memory buffer source filter
+ * Copyright (c) 2008 Vitor Sessak
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avfilter.h"
+#include "vsrc_buffer.h"
+
+typedef struct {
+    int64_t           pts;
+    AVFrame           frame;
+    int               has_frame;
+    int               h, w, pix_fmt;
+    AVRational        pixel_aspect;
+} BufferSourceContext;
+
+
+int av_vsrc_buffer_add_frame(AVFilterContext *buffer_filter, AVFrame *frame,
+                             int64_t pts, AVRational pixel_aspect)
+{
+    BufferSourceContext *c = buffer_filter->priv;
+
+    if (c->has_frame) {
+        av_log(buffer_filter, AV_LOG_ERROR,
+               "Buffering several frames is not supported. "
+               "Please consume all available frames before adding a new one.\n"
+            );
+        //return -1;
+    }
+
+    memcpy(c->frame.data    , frame->data    , sizeof(frame->data));
+    memcpy(c->frame.linesize, frame->linesize, sizeof(frame->linesize));
+    c->pts = pts;
+    c->pixel_aspect = pixel_aspect;
+    c->has_frame = 1;
+
+    return 0;
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    BufferSourceContext *c = ctx->priv;
+
+    if(args && sscanf(args, "%d:%d:%d", &c->w, &c->h, &c->pix_fmt) == 3)
+        return 0;
+
+    av_log(ctx, AV_LOG_ERROR, "init() expected 3 arguments:'%s'\n", args);
+    return -1;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    BufferSourceContext *c = ctx->priv;
+    enum PixelFormat pix_fmts[] = { c->pix_fmt, PIX_FMT_NONE };
+
+    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int config_props(AVFilterLink *link)
+{
+    BufferSourceContext *c = link->src->priv;
+
+    link->w = c->w;
+    link->h = c->h;
+
+    return 0;
+}
+
+
+static int request_frame(AVFilterLink *link)
+{
+    BufferSourceContext *c = link->src->priv;
+    AVFilterPicRef *picref;
+
+    if (!c->has_frame) {
+        av_log(link->src, AV_LOG_ERROR,
+               "request_frame() called with no available frame!\n");
+        //return -1;
+    }
+
+    /* This picture will be needed unmodified later for decoding the next
+     * frame */
+    picref = avfilter_get_video_buffer(link, AV_PERM_WRITE | AV_PERM_PRESERVE |
+                                       AV_PERM_REUSE2,
+                                       link->w, link->h);
+
+    av_picture_copy((AVPicture *)&picref->data, (AVPicture *)&c->frame,
+                    picref->pic->format, link->w, link->h);
+
+    picref->pts = c->pts;
+    picref->pixel_aspect = c->pixel_aspect;
+    avfilter_start_frame(link, avfilter_ref_pic(picref, ~0));
+    avfilter_draw_slice(link, 0, link->h, 1);
+    avfilter_end_frame(link);
+    avfilter_unref_pic(picref);
+
+    c->has_frame = 0;
+
+    return 0;
+}
+
+static int poll_frame(AVFilterLink *link)
+{
+    BufferSourceContext *c = link->src->priv;
+    return !!(c->has_frame);
+}
+
+AVFilter avfilter_vsrc_buffer =
+{
+    .name      = "buffer",
+    .priv_size = sizeof(BufferSourceContext),
+    .query_formats = query_formats,
+
+    .init      = init,
+
+    .inputs    = (AVFilterPad[]) {{ .name = NULL }},
+    .outputs   = (AVFilterPad[]) {{ .name            = "default",
+                                    .type            = AVMEDIA_TYPE_VIDEO,
+                                    .request_frame   = request_frame,
+                                    .poll_frame      = poll_frame,
+                                    .config_props    = config_props, },
+                                  { .name = NULL}},
+};

libavfilter/vsrc_buffer.h

+/*
+ * Memory buffer source filter
+ * Copyright (c) 2008 Vitor Sessak
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+int av_vsrc_buffer_add_frame(AVFilterContext *buffer_filter, AVFrame *frame,
+                             int64_t pts, AVRational pixel_aspect);
+