lavu: add AV_FRAME_DATA_DOWNMIX_INFO side data type.

1 files changed, 114 insertions, 0 deletions

diff --git a/libavutil/downmix_info.h b/libavutil/downmix_info.h
new file mode 100644
index 0000000000..69969f6fbd
--- /dev/null
+++ b/libavutil/downmix_info.h
@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2014 Tim Walker <tdskywalker@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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,
+ * 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
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_DOWNMIX_INFO_H
+#define AVUTIL_DOWNMIX_INFO_H
+
+#include "frame.h"
+
+/**
+ * @file
+ * audio downmix medatata
+ */
+
+/**
+ * @addtogroup lavu_audio
+ * @{
+ */
+
+/**
+ * @defgroup downmix_info Audio downmix metadata
+ * @{
+ */
+
+/**
+ * Possible downmix types.
+ */
+enum AVDownmixType {
+    AV_DOWNMIX_TYPE_UNKNOWN, /**< Not indicated. */
+    AV_DOWNMIX_TYPE_LORO,    /**< Lo/Ro 2-channel downmix (Stereo). */
+    AV_DOWNMIX_TYPE_LTRT,    /**< Lt/Rt 2-channel downmix, Dolby Surround compatible. */
+    AV_DOWNMIX_TYPE_DPLII,   /**< Lt/Rt 2-channel downmix, Dolby Pro Logic II compatible. */
+    AV_DOWNMIX_TYPE_NB       /**< Number of downmix types. Not part of ABI. */
+};
+
+/**
+ * This structure describes optional metadata relevant to a downmix procedure.
+ *
+ * All fields are set by the decoder to the value indicated in the audio
+ * bitstream (if present), or to a "sane" default otherwise.
+ */
+typedef struct AVDownmixInfo {
+    /**
+     * Type of downmix preferred by the mastering engineer.
+     */
+    enum AVDownmixType preferred_downmix_type;
+
+    /**
+     * Absolute scale factor representing the nominal level of the center
+     * channel during a regular downmix.
+     */
+    double center_mix_level;
+
+    /**
+     * Absolute scale factor representing the nominal level of the center
+     * channel during an Lt/Rt compatible downmix.
+     */
+    double center_mix_level_ltrt;
+
+    /**
+     * Absolute scale factor representing the nominal level of the surround
+     * channels during a regular downmix.
+     */
+    double surround_mix_level;
+
+    /**
+     * Absolute scale factor representing the nominal level of the surround
+     * channels during an Lt/Rt compatible downmix.
+     */
+    double surround_mix_level_ltrt;
+
+    /**
+     * Absolute scale factor representing the level at which the LFE data is
+     * mixed into L/R channels during downmixing.
+     */
+    double lfe_mix_level;
+} AVDownmixInfo;
+
+/**
+ * Get a frame's AV_FRAME_DATA_DOWNMIX_INFO side data for editing.
+ *
+ * The side data is created and added to the frame if it's absent.
+ *
+ * @param frame the frame for which the side data is to be obtained.
+ *
+ * @return the AVDownmixInfo structure to be edited by the caller.
+ */
+AVDownmixInfo *av_downmix_info_update_side_data(AVFrame *frame);
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+#endif /* AVUTIL_DOWNMIX_INFO_H */