[FFmpeg-devel] [PATCH 2/5] lavfi: add aformat filter

[Mina Nagy Zaki]

---
 doc/filters.texi         |   21 +++++++++
 libavfilter/Makefile     |    1 +
 libavfilter/af_aformat.c |  113 ++++++++++++++++++++++++++++++++++++++++++++++
 libavfilter/allfilters.c |    1 +
 4 files changed, 136 insertions(+), 0 deletions(-)
 create mode 100644 libavfilter/af_aformat.c

diff --git a/doc/filters.texi b/doc/filters.texi
index 33d6496..8dc1c15 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -99,6 +99,27 @@ build.
 
 Below is a description of the currently available audio filters.
 
+ at section aformat
+
+Convert the input audio to one of the specified formats. The framework will
+negotiate the most appropriate format to minimize conversions.
+
+The filter accepts three lists of formats, separated by ":",
+"sample_formats:channel_layouts:packing"
+
+Elements in each list are separated by "," which has to be escaped in the
+filtergraph specification.
+
+The special parameter "all", in place of a list of elements, signifies all
+supported formats.
+
+Some examples follow:
+ at example
+aformat=u8\\,s16:mono:packed
+
+aformat=s16:mono\\,stereo:all
+ at end example
+
 @section anull
 
 Pass the audio source unchanged to the output.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 6007fed..865ba1e 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -18,6 +18,7 @@ OBJS = allfilters.o                                                     \
 
 OBJS-$(CONFIG_AVCODEC)                       += avcodec.o
 
+OBJS-$(CONFIG_AFORMAT_FILTER)                += af_aformat.o
 OBJS-$(CONFIG_ANULL_FILTER)                  += af_anull.o
 
 OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o
diff --git a/libavfilter/af_aformat.c b/libavfilter/af_aformat.c
new file mode 100644
index 0000000..d3bf96c
--- /dev/null
+++ b/libavfilter/af_aformat.c
@@ -0,0 +1,113 @@
+/*
+ * 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
+ * format and noformat audio filters
+ */
+
+#include "libavutil/audioconvert.h"
+#include "avfilter.h"
+#include "internal.h"
+
+typedef struct {
+    AVFilterFormats *formats, *chlayouts, *packing;
+} AFormatContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    AFormatContext * const aformat = ctx->priv;
+    char *arg, *fmt_str;
+    int64_t fmt;
+
+    arg = strsep(&args, ":");
+    if (!arg) goto arg_fail;
+    if (!strcmp(arg, "all")) {
+        aformat->formats = avfilter_all_formats(AVMEDIA_TYPE_AUDIO);
+    } else {
+        while (fmt_str = strsep(&arg, ",")) {
+            fmt = ff_parse_sample_format(fmt_str, ctx);
+            if (fmt == -1) return AVERROR(EINVAL);
+            avfilter_add_format(&aformat->formats, fmt);
+        }
+    }
+
+    arg = strsep(&args, ":");
+    if (!arg) goto arg_fail;
+    if (!strcmp(arg, "all")) {
+        aformat->chlayouts = avfilter_all_channel_layouts();
+    } else {
+        while (fmt_str = strsep(&arg, ",")) {
+            fmt = ff_parse_channel_layout(fmt_str, ctx);
+            if (fmt == -1) return AVERROR(EINVAL);
+            avfilter_add_format(&aformat->chlayouts, fmt);
+        }
+    }
+
+    arg = strsep(&args, ":");
+    if (!arg) goto arg_fail;
+    if (!strcmp(arg, "all")) {
+        aformat->packing = avfilter_all_packing_formats();
+    } else {
+        while (fmt_str = strsep(&arg, ",")) {
+            fmt = ff_parse_packing_format(fmt_str, ctx);
+            if (fmt == -1) return AVERROR(EINVAL);
+            avfilter_add_format(&aformat->packing, fmt);
+        }
+    }
+
+    return 0;
+
+arg_fail:
+    av_log(ctx, AV_LOG_ERROR, "Please provide the required arguments "
+                              "sample_fmts:channel_layouts:packing_fmts\n");
+    return AVERROR(EINVAL);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AFormatContext * const aformat = ctx->priv;
+
+    avfilter_set_common_sample_formats (ctx, aformat->formats);
+    avfilter_set_common_channel_layouts(ctx, aformat->chlayouts);
+    avfilter_set_common_packing_formats(ctx, aformat->packing);
+    return 0;
+}
+
+static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamplesref)
+{
+    avfilter_filter_samples(inlink->dst->outputs[0], insamplesref);
+}
+
+AVFilter avfilter_af_aformat = {
+    .name          = "aformat",
+    .description   = NULL_IF_CONFIG_SMALL("Convert the input audio to one of the specified formats."),
+    .init          = init,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(AFormatContext),
+
+    .inputs        = (AVFilterPad[]) {{ .name            = "default",
+                                        .type            = AVMEDIA_TYPE_AUDIO,
+                                        .filter_samples  = filter_samples},
+                                      { .name = NULL}},
+    .outputs       = (AVFilterPad[]) {{ .name            = "default",
+                                        .type            = AVMEDIA_TYPE_AUDIO},
+                                      { .name = NULL}},
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 99f7bc4..56baa50 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -34,6 +34,7 @@ void avfilter_register_all(void)
         return;
     initialized = 1;
 
+    REGISTER_FILTER (AFORMAT,     aformat,     af);
     REGISTER_FILTER (ANULL,       anull,       af);
 
     REGISTER_FILTER (ANULLSRC,    anullsrc,    asrc);
-- 
1.7.4.4