chan.c

这个库实现了录象功能

/*******************************************************************************
 chan.c

 libquicktime - A library for reading and writing quicktime/avi/mp4 files.
 http://libquicktime.sourceforge.net

 Copyright (C) 2002 Heroine Virtual Ltd.
 Copyright (C) 2002-2007 Members of the libquicktime project.

 This library 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.

 This library 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 this library; if not, write to the Free Software Foundation, Inc., 51
 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*******************************************************************************/ 

#include "lqt_private.h"
#include <stdlib.h>

/*
 *  Quicktime chan atom.
 *
 *  I didn't find any official documentation about the channel
 *  description atom (which is needed for multichannel support).
 *  There is, however this document about the CAF format by Apple:
 *
 *  http://developer.apple.com/documentation/MusicAudio/Reference/CAFSpec/index.html

 *  The guess was, that the chan atoms in CAF and Quicktime files are the same,
 *  and the guess turned out to be true :)
 */

typedef enum
  {
    CHANNEL_LABEL_Unknown    = 0xFFFFFFFF,   // unknown role or uspecified
                                                // other use for channel
    CHANNEL_LABEL_Unused     = 0,            // channel is present, but
                                                // has no intended role or destination
    CHANNEL_LABEL_UseCoordinates         = 100,  // channel is described
                                                // solely by the mCoordinates fields
    
    CHANNEL_LABEL_Left                   = 1,
    CHANNEL_LABEL_Right                  = 2,
    CHANNEL_LABEL_Center                 = 3,
    CHANNEL_LABEL_LFEScreen              = 4,
    CHANNEL_LABEL_LeftSurround           = 5,    // WAVE (.wav files): "Back Left"
    CHANNEL_LABEL_RightSurround          = 6,    // WAVE: "Back Right"
    CHANNEL_LABEL_LeftCenter             = 7,    
    CHANNEL_LABEL_RightCenter            = 8,
    CHANNEL_LABEL_CenterSurround         = 9,    // WAVE: "Back Center or
                                                    // plain "Rear Surround"
    CHANNEL_LABEL_LeftSurroundDirect     = 10,   // WAVE: "Side Left"
    CHANNEL_LABEL_RightSurroundDirect    = 11,   // WAVE: "Side Right"
    CHANNEL_LABEL_TopCenterSurround      = 12,
    CHANNEL_LABEL_VerticalHeightLeft     = 13,   // WAVE: "Top Front Left
    CHANNEL_LABEL_VerticalHeightCenter   = 14,   // WAVE: "Top Front Center
    CHANNEL_LABEL_VerticalHeightRight    = 15,   // WAVE: "Top Front Right
    CHANNEL_LABEL_TopBackLeft            = 16,
    CHANNEL_LABEL_TopBackCenter          = 17,
    CHANNEL_LABEL_TopBackRight           = 18,
    CHANNEL_LABEL_RearSurroundLeft       = 33,
    CHANNEL_LABEL_RearSurroundRight      = 34,
    CHANNEL_LABEL_LeftWide               = 35,
    CHANNEL_LABEL_RightWide              = 36,
    CHANNEL_LABEL_LFE2                   = 37,
    CHANNEL_LABEL_LeftTotal              = 38,   // matrix encoded 4 channels
    CHANNEL_LABEL_RightTotal             = 39,   // matrix encoded 4 channels
    CHANNEL_LABEL_HearingImpaired        = 40,
    CHANNEL_LABEL_Narration              = 41,
    CHANNEL_LABEL_Mono                   = 42,
    CHANNEL_LABEL_DialogCentricMix       = 43,
    
    CHANNEL_LABEL_CenterSurroundDirect   = 44,   // back center, non diffuse

    // first order ambisonic channels
    
    CHANNEL_LABEL_Ambisonic_W            = 200,
    CHANNEL_LABEL_Ambisonic_X            = 201,
    CHANNEL_LABEL_Ambisonic_Y            = 202,
    CHANNEL_LABEL_Ambisonic_Z            = 203,
    
    // Mid/Side Recording

    CHANNEL_LABEL_MS_Mid                 = 204,
    CHANNEL_LABEL_MS_Side                = 205,
    
    // X-Y Recording

    CHANNEL_LABEL_XY_X                   = 206,
    CHANNEL_LABEL_XY_Y                   = 207,
    
    // other

    CHANNEL_LABEL_HeadphonesLeft         = 301,
    CHANNEL_LABEL_HeadphonesRight        = 302,
    CHANNEL_LABEL_ClickTrack             = 304,
    CHANNEL_LABEL_ForeignLanguage        = 305
  } channel_label_t;

static struct
  {
  channel_label_t label;
  char * name;
  }
channel_label_names[] =
  {
    { CHANNEL_LABEL_Unknown,              "Unknown" },
    { CHANNEL_LABEL_Unused,               "Unused" },
                                                // has no intended role or destination
    { CHANNEL_LABEL_UseCoordinates,       "Use Coordinates" },
    
    { CHANNEL_LABEL_Left,                 "Left" },
    { CHANNEL_LABEL_Right,                "Right" },
    { CHANNEL_LABEL_Center,               "Center" },
    { CHANNEL_LABEL_LFEScreen,            "LFE" },
    { CHANNEL_LABEL_LeftSurround,         "Left Surround" },  // WAVE (.wav files): Back Left
    { CHANNEL_LABEL_RightSurround,        "Right Surround" }, // WAVE: "Back Right"
    { CHANNEL_LABEL_LeftCenter,           "Left Center" },
    { CHANNEL_LABEL_RightCenter,          "Right Center" },
    { CHANNEL_LABEL_CenterSurround,       "Center Surround" }, // WAVE: "Back Center or
                                                               // plain "Rear Surround"
    { CHANNEL_LABEL_LeftSurroundDirect,   "Side Left" },       // WAVE: "Side Left"
    { CHANNEL_LABEL_RightSurroundDirect,  "Side Right" },      // WAVE: "Side Right"
    { CHANNEL_LABEL_TopCenterSurround,    "Top Center Surround" },
    { CHANNEL_LABEL_VerticalHeightLeft,   "Top Front Left" },  // WAVE: Top Front Left
    { CHANNEL_LABEL_VerticalHeightCenter, "Top Front Center" },  // WAVE: Top Front Center
    { CHANNEL_LABEL_VerticalHeightRight,  "Top Front Right" },   // WAVE: "Top Front Right"
    { CHANNEL_LABEL_TopBackLeft,          "Top Back Left" }, 
    { CHANNEL_LABEL_TopBackCenter,        "Top Back Center" } ,
    { CHANNEL_LABEL_TopBackRight,         "Top Back Right" },
    { CHANNEL_LABEL_RearSurroundLeft,     "Rear Surround Left" },
    { CHANNEL_LABEL_RearSurroundRight,    "Rear Surround Right" },
    { CHANNEL_LABEL_LeftWide,             "Left Wide" },
    { CHANNEL_LABEL_RightWide,            "Right Wide" },
    { CHANNEL_LABEL_LFE2,                 "LFE 2" },
    { CHANNEL_LABEL_LeftTotal,            "Left Total" },    // matrix encoded 4 channels
    { CHANNEL_LABEL_RightTotal,           "Right Total" },   // matrix encoded 4 channels
    { CHANNEL_LABEL_HearingImpaired,      "Hearing Impaired" },
    { CHANNEL_LABEL_Narration,            "Narration" },
    { CHANNEL_LABEL_Mono,                 "Mono" },
    { CHANNEL_LABEL_DialogCentricMix,     "Dialog Centric Mix" },
    
    { CHANNEL_LABEL_CenterSurroundDirect, "Center Surround Direct" },  // back center, non diffuse

    // first order ambisonic channels
    
    { CHANNEL_LABEL_Ambisonic_W, "Ambisonic W" },
    { CHANNEL_LABEL_Ambisonic_X, "Ambisonic X" },
    { CHANNEL_LABEL_Ambisonic_Y, "Ambisonic Y" },
    { CHANNEL_LABEL_Ambisonic_Z, "Ambisonic Z" },
    
    // Mid/Side Recording

    { CHANNEL_LABEL_MS_Mid,  "MS Mid" },
    { CHANNEL_LABEL_MS_Side,  "MS Side" },
    
    // X-Y Recording

    { CHANNEL_LABEL_XY_X, "Label XY X" },
    { CHANNEL_LABEL_XY_Y, "Label XY Y" },
    
    // other

    { CHANNEL_LABEL_HeadphonesLeft, "Headphones Left" },
    { CHANNEL_LABEL_HeadphonesRight, "Headphones Right" },
    { CHANNEL_LABEL_ClickTrack,      "Click Track" },
    { CHANNEL_LABEL_ForeignLanguage,  "Foreign Language" },
    
  };

static const char * get_channel_name(channel_label_t label)
  {
  int i;
  for(i = 0; i < sizeof(channel_label_names)/sizeof(channel_label_names[0]); i++)
    {
    if(channel_label_names[i].label == label)
      return channel_label_names[i].name;
    }
  return (char*)0;
  }

typedef enum
  {
    CHANNEL_BIT_Left                 = (1<<0),
    CHANNEL_BIT_Right                = (1<<1),
    CHANNEL_BIT_Center               = (1<<2),
    CHANNEL_BIT_LFEScreen            = (1<<3),
    CHANNEL_BIT_LeftSurround         = (1<<4),   // WAVE: "Back Left"
    CHANNEL_BIT_RightSurround        = (1<<5),   // WAVE: "Back Right"
    CHANNEL_BIT_LeftCenter           = (1<<6),
    CHANNEL_BIT_RightCenter          = (1<<7),
    CHANNEL_BIT_CenterSurround       = (1<<8),   // WAVE: "Back Center"
    CHANNEL_BIT_LeftSurroundDirect   = (1<<9),   // WAVE: "Side Left"
    CHANNEL_BIT_RightSurroundDirect  = (1<<10), // WAVE: "Side Right"
    CHANNEL_BIT_TopCenterSurround    = (1<<11),
    CHANNEL_BIT_VerticalHeightLeft   = (1<<12), // WAVE: "Top Front Left"
    CHANNEL_BIT_VerticalHeightCenter = (1<<13), // WAVE: "Top Front Center"
    CHANNEL_BIT_VerticalHeightRight  = (1<<14), // WAVE: "Top Front Right"
    CHANNEL_BIT_TopBackLeft          = (1<<15),
    CHANNEL_BIT_TopBackCenter        = (1<<16),
    CHANNEL_BIT_TopBackRight         = (1<<17)
  } channel_bit_t;

static struct
  {
  channel_bit_t bit;
  channel_label_t label;
  }
channel_bits[] =
  {
    { CHANNEL_BIT_Left,                 CHANNEL_LABEL_Left },
    { CHANNEL_BIT_Right,                CHANNEL_LABEL_Right },
    { CHANNEL_BIT_Center,               CHANNEL_LABEL_Center },
    { CHANNEL_BIT_LFEScreen,            CHANNEL_LABEL_LFEScreen },
    { CHANNEL_BIT_LeftSurround,         CHANNEL_LABEL_LeftSurround }, // WAVE: "Back Left"
    { CHANNEL_BIT_RightSurround,        CHANNEL_LABEL_RightSurround },// WAVE: "Back Right"
    { CHANNEL_BIT_LeftCenter,           CHANNEL_LABEL_LeftCenter    },
    { CHANNEL_BIT_RightCenter,          CHANNEL_LABEL_RightCenter },
    { CHANNEL_BIT_CenterSurround,       CHANNEL_LABEL_CenterSurround }, // WAVE: "Back Center"
    { CHANNEL_BIT_LeftSurroundDirect,   CHANNEL_LABEL_LeftSurroundDirect },   // WAVE: "Side Left"
    { CHANNEL_BIT_RightSurroundDirect,  CHANNEL_LABEL_RightSurroundDirect }, // WAVE: "Side Right"
    { CHANNEL_BIT_TopCenterSurround,    CHANNEL_LABEL_TopCenterSurround },
    { CHANNEL_BIT_VerticalHeightLeft,   CHANNEL_LABEL_VerticalHeightLeft }, // WAVE: "Top Front Left"
    { CHANNEL_BIT_VerticalHeightCenter, CHANNEL_LABEL_VerticalHeightCenter }, // WAVE: "Top Front Center"
    { CHANNEL_BIT_VerticalHeightRight,  CHANNEL_LABEL_VerticalHeightRight }, // WAVE: "Top Front Right"
    { CHANNEL_BIT_TopBackLeft,          CHANNEL_LABEL_TopBackLeft },
    { CHANNEL_BIT_TopBackCenter,        CHANNEL_LABEL_TopBackCenter },
    { CHANNEL_BIT_TopBackRight,         CHANNEL_LABEL_TopBackRight },
  };

static channel_label_t channel_bit_2_channel_label(uint32_t bit)
  {
  int i;
  for(i = 0; i < sizeof(channel_bits) / sizeof(channel_bits[0]); i++)
    {
    if(bit == channel_bits[i].bit)
      return channel_bits[i].label;
    }
  return CHANNEL_LABEL_Unknown;
  }

static struct
  {
  lqt_channel_t lqt_channel;
  channel_label_t channel_label;
  }
lqt_channels[] =
  {
    { LQT_CHANNEL_UNKNOWN,            CHANNEL_LABEL_Unknown },
    { LQT_CHANNEL_FRONT_LEFT,         CHANNEL_LABEL_Left },
    { LQT_CHANNEL_FRONT_RIGHT,        CHANNEL_LABEL_Right },