hb_audio_resample: libvaresample wrapper.

Avoids having code that's mostly identical in multiple files.



git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@4838 b64f7644-9d1e-0410-96f1-a4d463321fa5

1 files changed, 81 insertions, 0 deletions

diff --git a/libhb/audio_resample.h b/libhb/audio_resample.h
new file mode 100644
index 000000000..5982905e6
--- /dev/null
+++ b/libhb/audio_resample.h
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+/* audio_resample.h
+ *
+ * Copyright (c) 2003-2012 HandBrake Team
+ * This file is part of the HandBrake source code
+ * Homepage: <http://handbrake.fr/>
+ * It may be used under the terms of the GNU General Public License v2.
+ * For full terms see the file COPYING file or visit http://www.gnu.org/licenses/gpl-2.0.html
+ */
+
+/* Implements a libavresample wrapper for convenience.
+ *
+ * Supports sample_fmt and channel_layout conversion.
+ *
+ * sample_rate conversion will come later (libavresample doesn't support
+ * sample_rate conversion with float samples yet). */
+
+#ifndef AUDIO_RESAMPLE_H
+#define AUDIO_RESAMPLE_H
+
+#include <stdint.h>
+#include "libavutil/audioconvert.h"
+#include "libavresample/avresample.h"
+
+typedef struct
+{
+    int resample_needed;
+    AVAudioResampleContext *avresample;
+
+    struct
+    {
+        int channels;
+        int linesize;
+        uint64_t channel_layout;
+        enum AVSampleFormat sample_fmt;
+    } in;
+
+    struct
+    {
+        int channels;
+        int linesize;
+        int sample_size;
+        uint64_t channel_layout;
+        enum AVSampleFormat sample_fmt;
+        enum AVMatrixEncoding matrix_encoding;
+    } out;
+} hb_audio_resample_t;
+
+/* Initialize an hb_audio_resample_t to convert audio to the requested
+ * sample_fmt and channel_layout, using the specified matrix_encoding.
+ *
+ * Input characteristics are set via hb_audio_resample_update().
+ */
+hb_audio_resample_t* hb_audio_resample_init(enum AVSampleFormat output_sample_fmt,
+                                            uint64_t output_channel_layout,
+                                            enum AVMatrixEncoding matrix_encoding);
+
+/* Update an hb_audio_resample_t, setting the input sample characteristics.
+ *
+ * Can be called whenever the input type may change.
+ *
+ * new_channel_layout is sanitized automatically.
+ */
+int                  hb_audio_resample_update(hb_audio_resample_t *resample,
+                                              enum AVSampleFormat new_sample_fmt,
+                                              uint64_t new_channel_layout,
+                                              int new_channels);
+
+/* Free an hb_audio_remsample_t. */
+void                 hb_audio_resample_free(hb_audio_resample_t *resample);
+
+/* Convert input samples to the requested output characteristics
+ * (sample_fmt and channel_layout + matrix_encoding).
+ *
+ * Returns an hb_buffer_t with the converted output.
+ *
+ * resampling is only done when necessary.
+ */
+hb_buffer_t*         hb_audio_resample(hb_audio_resample_t *resample,
+                                       void *samples, int nsamples);
+
+#endif /* AUDIO_RESAMPLE_H */