lavfi: add asink_abuffer - audio buffer sink

Signed-off-by: Stefano Sabatini <stefano.sabatini-lala@poste.it>

doc/filters.texi

@@ -144,6 +144,17 @@ anullsrc=48000:mono
 
 Below is a description of the currently available audio sinks.
 
+@section abuffersink
+
+Buffer audio frames, and make them available to the end of filter chain.
+
+This sink is mainly intended for programmatic use, in particular
+through the interface defined in @file{libavfilter/asink_abuffer.h}.
+
+It requires a pointer to a ABufferSinkContext structure, which defines the
+incoming buffers' format, to be passed as the opaque parameter to
+@code{avfilter_init_filter} for initialization.
+
 @section anullsink
 
 Null audio sink, do absolutely nothing with the input audio. It is

libavfilter/Makefile

@@ -22,6 +22,7 @@ OBJS-$(CONFIG_ANULL_FILTER)                  += af_anull.o
 
 OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o
 
+OBJS-$(CONFIG_ABUFFERSINK_FILTER)            += asink_abuffer.o
 OBJS-$(CONFIG_ANULLSINK_FILTER)              += asink_anullsink.o
 
 OBJS-$(CONFIG_BLACKFRAME_FILTER)             += vf_blackframe.o

libavfilter/allfilters.c

@@ -38,6 +38,7 @@ void avfilter_register_all(void)
 
     REGISTER_FILTER (ANULLSRC,    anullsrc,    asrc);
 
+    REGISTER_FILTER (ABUFFERSINK, abuffersink, asink);
     REGISTER_FILTER (ANULLSINK,   anullsink,   asink);
 
     REGISTER_FILTER (BLACKFRAME,  blackframe,  vf);

libavfilter/asink_abuffer.c

+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ * Copyright (c) 2011 Mina Nagy Zaki
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * audio buffer sink
+ */
+
+#include "avfilter.h"
+#include "asink_abuffer.h"
+
+static void filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref)
+{
+}
+
+static int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    if (!opaque) {
+        av_log(ctx, AV_LOG_ERROR, "Opaque field required, please pass"
+                                  " an initialized ABufferSinkContext");
+        return AVERROR(EINVAL);
+    }
+    memcpy(ctx->priv, opaque, sizeof(ABufferSinkContext));
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    ABufferSinkContext *abuffersink = ctx->priv;
+    AVFilterFormats *formats;
+    int ret;
+
+    formats = NULL;
+    if ((ret = avfilter_add_format(&formats, abuffersink->sample_fmt)) < 0)
+        return ret;
+    avfilter_set_common_sample_formats(ctx, formats);
+
+    formats = NULL;
+    if ((ret = avfilter_add_format(&formats, abuffersink->channel_layout)) < 0)
+        return ret;
+    avfilter_set_common_channel_layouts(ctx, formats);
+
+    formats = NULL;
+    if ((ret = avfilter_add_format(&formats, abuffersink->planar)) < 0)
+        return ret;
+    avfilter_set_common_packing_formats(ctx, formats);
+
+    return 0;
+}
+
+int av_asink_abuffer_get_audio_buffer_ref(AVFilterContext *abuffersink,
+                                          AVFilterBufferRef **samplesref,
+                                          int av_unused flags)
+{
+    int ret;
+    AVFilterLink * const inlink = abuffersink->inputs[0];
+
+    if ((ret = avfilter_request_frame(inlink)))
+        return ret;
+    if (!inlink->cur_buf)
+        return AVERROR(EINVAL);
+    *samplesref = inlink->cur_buf;
+    inlink->cur_buf = NULL;
+
+    return 0;
+}
+
+AVFilter avfilter_asink_abuffersink = {
+    .name      = "abuffersink",
+    .description = NULL_IF_CONFIG_SMALL("Buffer audio frames, and make them available to the end of the filter graph."),
+    .init      = init,
+    .priv_size = sizeof(ABufferSinkContext),
+    .query_formats = query_formats,
+
+    .inputs    = (AVFilterPad[]) {{ .name           = "default",
+                                    .type           = AVMEDIA_TYPE_AUDIO,
+                                    .filter_samples = filter_samples,
+                                    .min_perms      = AV_PERM_READ, },
+                                  { .name = NULL }},
+    .outputs   = (AVFilterPad[]) {{ .name = NULL }},
+};
+

libavfilter/asink_abuffer.h

+/*
+ * 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
+ */
+
+#ifndef AVFILTER_ASINK_ABUFFER_H
+#define AVFILTER_ASINK_ABUFFER_H
+
+/**
+ * @file
+ * audio buffer sink API
+ */
+
+#include "avfilter.h"
+
+typedef struct {
+    enum AVSampleFormat sample_fmt;
+    int64_t channel_layout;
+    int planar;
+} ABufferSinkContext;
+
+
+/**
+ * Get an audio buffer from abuffersink and put it in samplesref.
+ *
+ * @param abuffersink pointer to an abuffersink context
+ * @param flags unused
+ * @return >= 0 in case of success, a negative AVERROR code in case of failure
+ */
+int av_asink_abuffer_get_audio_buffer_ref(AVFilterContext *abuffersink,
+                                          AVFilterBufferRef **samplesref,
+                                          int av_unused flags);
+
+#endif /* AVFILTER_ASINK_ABUFFER_H */

libavfilter/avfilter.h

@@ -29,8 +29,8 @@
 #include "libavutil/rational.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  2
-#define LIBAVFILTER_VERSION_MINOR 27
-#define LIBAVFILTER_VERSION_MICRO  5
+#define LIBAVFILTER_VERSION_MINOR 28
+#define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \