Android4.0.1中各个Player的功能

1. Android4.0.1中默认定义了4个真正的Player,具体情况如下：

 static sp<MediaPlayerBase> createPlayer(player_type playerType, void* cookie,
         notify_callback_f notifyFunc)
 {
     sp<MediaPlayerBase> p;
     switch (playerType) {
         case SONIVOX_PLAYER:
             LOGV(" create MidiFile");
             p = new MidiFile();
             break;
         case STAGEFRIGHT_PLAYER:
             LOGV(" create StagefrightPlayer");
             p = new StagefrightPlayer;
             break;
         case NU_PLAYER:
             LOGV(" create NuPlayer");
             p = new NuPlayerDriver;
             break;
         case TEST_PLAYER:
             LOGV("Create Test Player stub");
             p = new TestPlayerStub();
             break;
         default:
             LOGE("Unknown player type: %d", playerType);
             return NULL;
     }
     if (p != NULL) {
         if (p->initCheck() == NO_ERROR) {
             p->setNotifyCallback(cookie, notifyFunc);
         } else {
             p.clear();
         }
     }
     if (p == NULL) {
         LOGE("Failed to create player object");
     }
     return p;
 }

2. 每个Player的专长是什么呢？

Player Type	Feature Description
TEST_PLAYER	url以test:开始的。如test:xxx
NU_PLAYER	url以http://或https://开始的，且url以.m3u8结束或url中包含有m3u8字符串
SONIVOX_PLAYER	处理url中扩展名为：.mid,.midi,.smf,.xmf,.imy,.rtttl,.rtx,.ota的媒体文件
STAGEFRIGHT_PLAYER	它是一个大好人，前面三位不能处理的都交给它来处理，不知能力是否有如此强大

以上言论以代码为证，获取player type的代码如下：

 player_type getPlayerType(const char* url)
 {
     if (TestPlayerStub::canBeUsed(url)) {
         return TEST_PLAYER;
     }

     if (!strncasecmp("http://", url, 7)
             || !strncasecmp("https://", url, 8)) {
         size_t len = strlen(url);
         if (len >= 5 && !strcasecmp(".m3u8", &url[len - 5])) {
             return NU_PLAYER;
         }

         if (strstr(url,"m3u8")) {
             return NU_PLAYER;
         }
     }

     // use MidiFile for MIDI extensions
     int lenURL = strlen(url);
     for (int i = 0; i < NELEM(FILE_EXTS); ++i) {
         int len = strlen(FILE_EXTS[i].extension);
         int start = lenURL - len;
         if (start > 0) {
             if (!strncasecmp(url + start, FILE_EXTS[i].extension, len)) {
                 return FILE_EXTS[i].playertype;
             }
         }
     }

     return getDefaultPlayerType();
 }

 player_type getPlayerType(const char* url)
 {
     if (TestPlayerStub::canBeUsed(url)) {
         return TEST_PLAYER;
     }

     if (!strncasecmp("http://", url, 7)
             || !strncasecmp("https://", url, 8)) {
         size_t len = strlen(url);
         if (len >= 5 && !strcasecmp(".m3u8", &url[len - 5])) {
             return NU_PLAYER;
         }

         if (strstr(url,"m3u8")) {
             return NU_PLAYER;
         }
     }

     // use MidiFile for MIDI extensions
     int lenURL = strlen(url);
     for (int i = 0; i < NELEM(FILE_EXTS); ++i) {
         int len = strlen(FILE_EXTS[i].extension);
         int start = lenURL - len;
         if (start > 0) {
             if (!strncasecmp(url + start, FILE_EXTS[i].extension, len)) {
                 return FILE_EXTS[i].playertype;
             }
         }
     }

     return getDefaultPlayerType();
 }

如果你想增加自己的player,以上两个函数都需要修改。

现在对整个媒体系统基本上有一个清晰的框架了，就突发奇想，到底在StagefrightPlayer如何增加自己的硬件解码呢? 很好奇，想一探究竟...