1 files changed, 105 insertions, 12 deletions

diff --git a/libavfilter/asrc_anullsrc.c b/libavfilter/asrc_anullsrc.c
index b1a449cdbe..28d4500a25 100644
--- a/libavfilter/asrc_anullsrc.c
+++ b/libavfilter/asrc_anullsrc.c
@@ -1,18 +1,21 @@
 /*
- * This file is part of Libav.
+ * Copyright 2010 S.N. Hemanth Meenakshisundaram <smeenaks ucsd edu>
+ * Copyright 2010 Stefano Sabatini <stefano.sabatini-lala poste it>
  *
- * Libav is free software; you can redistribute it and/or
+ * 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.
  *
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -26,28 +29,118 @@
 
 #include "libavutil/channel_layout.h"
 #include "libavutil/internal.h"
+#include "libavutil/opt.h"
+#include "audio.h"
 #include "avfilter.h"
 #include "internal.h"
 
-static int request_frame(AVFilterLink *link)
+typedef struct {
+    const AVClass *class;
+    char   *channel_layout_str;
+    uint64_t channel_layout;
+    char   *sample_rate_str;
+    int     sample_rate;
+    int nb_samples;             ///< number of samples per requested frame
+    int64_t pts;
+} ANullContext;
+
+#define OFFSET(x) offsetof(ANullContext, x)
+#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption anullsrc_options[]= {
+    { "channel_layout", "set channel_layout", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, FLAGS },
+    { "cl",             "set channel_layout", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, FLAGS },
+    { "sample_rate",    "set sample rate",    OFFSET(sample_rate_str)   , AV_OPT_TYPE_STRING, {.str = "44100"}, 0, 0, FLAGS },
+    { "r",              "set sample rate",    OFFSET(sample_rate_str)   , AV_OPT_TYPE_STRING, {.str = "44100"}, 0, 0, FLAGS },
+    { "nb_samples",     "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
+    { "n",              "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(anullsrc);
+
+static av_cold int init(AVFilterContext *ctx)
 {
-    return AVERROR_EOF;
+    ANullContext *null = ctx->priv;
+    int ret;
+
+    if ((ret = ff_parse_sample_rate(&null->sample_rate,
+                                     null->sample_rate_str, ctx)) < 0)
+        return ret;
+
+    if ((ret = ff_parse_channel_layout(&null->channel_layout, NULL,
+                                        null->channel_layout_str, ctx)) < 0)
+        return ret;
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    ANullContext *null = ctx->priv;
+    int64_t chlayouts[] = { null->channel_layout, -1 };
+    int sample_rates[] = { null->sample_rate, -1 };
+
+    ff_set_common_formats        (ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO));
+    ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts));
+    ff_set_common_samplerates    (ctx, ff_make_format_list(sample_rates));
+
+    return 0;
+}
+
+static int config_props(AVFilterLink *outlink)
+{
+    ANullContext *null = outlink->src->priv;
+    char buf[128];
+
+    av_get_channel_layout_string(buf, sizeof(buf), 0, null->channel_layout);
+    av_log(outlink->src, AV_LOG_VERBOSE,
+           "sample_rate:%d channel_layout:'%s' nb_samples:%d\n",
+           null->sample_rate, buf, null->nb_samples);
+
+    return 0;
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    int ret;
+    ANullContext *null = outlink->src->priv;
+    AVFrame *samplesref;
+
+    samplesref = ff_get_audio_buffer(outlink, null->nb_samples);
+    if (!samplesref)
+        return AVERROR(ENOMEM);
+
+    samplesref->pts = null->pts;
+    samplesref->channel_layout = null->channel_layout;
+    samplesref->sample_rate = outlink->sample_rate;
+
+    ret = ff_filter_frame(outlink, av_frame_clone(samplesref));
+    av_frame_free(&samplesref);
+    if (ret < 0)
+        return ret;
+
+    null->pts += null->nb_samples;
+    return ret;
 }
 
 static const AVFilterPad avfilter_asrc_anullsrc_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
+        .config_props  = config_props,
         .request_frame = request_frame,
     },
     { NULL }
 };
 
 AVFilter ff_asrc_anullsrc = {
-    .name        = "anullsrc",
-    .description = NULL_IF_CONFIG_SMALL("Null audio source, never return audio frames."),
-
-    .inputs      = NULL,
-
-    .outputs     = avfilter_asrc_anullsrc_outputs,
+    .name          = "anullsrc",
+    .description   = NULL_IF_CONFIG_SMALL("Null audio source, return empty audio frames."),
+    .init          = init,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(ANullContext),
+    .inputs        = NULL,
+    .outputs       = avfilter_asrc_anullsrc_outputs,
+    .priv_class    = &anullsrc_class,
 };