add audio resampling, add ffmpeg support

libobs/media-io/audio-resampler.h

@@ -0,0 +1,38 @@
+/******************************************************************************
+    Copyright (C) 2013 by Hugh Bailey <obs.jim@gmail.com>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+#pragma once
+
+#include "../util/c99defs.h"
+#include "audio-io.h"
+
+struct audio_resampler;
+typedef struct audio_resampler *audio_resampler_t;
+
+struct resample_info {
+	uint32_t            samples_per_sec;
+	enum audio_format   format;
+	enum speaker_layout speakers;
+};
+
+EXPORT audio_resampler_t audio_resampler_create(struct resample_info *dst,
+		struct resample_info *src);
+EXPORT void audio_resampler_destroy(audio_resampler_t resampler);
+
+EXPORT bool audio_resampler_resample(audio_resampler_t resampler,
+		 void **output, uint32_t *out_frames,
+		 void *input, uint32_t in_frames);