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本文标签： Android MediaPlayer 本文是在《玩转 Android MediaPlayer之视频预加载》基础上做更进一步的优化，适应更多终端的MediaPlayer，不再唠叨预加载的作用和基础，有兴趣的读者请看上回。 MediaPlayer由厂家定制，不同终端的MediaPlayer略有差异，例如：有些MediaPlayer首次播放从头buffer，有些MdiaPlayer首次播放会多次Request，Range到网络媒体文件的头部、中间和文件尾，再从指定位置buffer...本文所做的优化就是适应播放前多次Request的MediaPlayer。 决定预加载效果好坏由三因素决定：
码率低、网速快的情况没必要使用预加载，码率中等、网速一般的情况合适使用。另外，缓冲文件也不能设置太大：过大的缓冲区会刷爆MediaPlayer内置的缓冲区，影响正常播放；再者，读取缓冲文件也耗时。
先看看本文程序的运行结果，以下是不使用预加载的运行LOG：
08-27 10:34:55.222: E//mnt/sdcard/ProxyBuffer/files(12949): --------共有0个缓存文件
以下是使用预加载的运行LOG，内容有点多，这个MediaPlayer就是首次播放前多次Request：
08-27 10:40:02.627: E//mnt/sdcard/ProxyBuffer/files(13769): --------共有0个缓存文件 08-27 10:40:10.787: E/HttpGetProxy(13769): com.proxy.HttpGetProxy.access$0 134line 08-27 10:40:10.787: E/HttpGetProxy(13769): com.proxy.HttpGetProxy$1.run 129line 08-27 10:40:10.787: E/HttpGetProxy(13769): ------------------------------------------------------------------ 08-27 10:40:10.792: E/HttpParser(13769): Range: bytes=0- 08-27 10:40:10.792: E/HttpParser(13769): Host: video.cztv.com 08-27 10:40:10.792: E/HttpParser(13769): Accept: */* 08-27 10:40:10.792: E/HttpParser(13769): Pragma: no-cache 08-27 10:40:10.792: E/HttpParser(13769): 08-27 10:40:10.792: E/HttpParser(13769): _prebufferFilePath:/mnt/sdcard/ProxyBuffer/files/videorzx201208151345010952759.mp4 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Date: Mon, 27 Aug 2012 02:33:24 GMT 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Server: Apache 08-27 10:40:11.762: E/HttpGetProxy<---(13769): X-Mod-H264-Streaming: version=2.2.7 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Last-Modified: Wed, 15 Aug 2012 06:24:38 GMT 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Accept-Ranges: bytes 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Cache-Control: max-age=315360000 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Expires: Thu, 25 Aug 2022 02:33:24 GMT 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Content-Type: video/mp4 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Powered-By-ChinaCache: HIT from 01006613Y4 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Content-Range: bytes 0-8311865/8311866 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Content-Length: 8311866 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Age: 407 08-27 10:40:11.762: E/HttpGetProxy<---(13769): Powered-By-ChinaCache: HIT from 01075913r4 08-27 10:40:11.762: E/HttpGetProxy<---(13769): 08-27 10:40:11.777: E/HttpGetProxy(13769): .........over.......... 08-27 10:40:11.782: E/HttpParser(13769): Range: bytes=101901- 08-27 10:40:11.782: E/HttpParser(13769): Host: video.cztv.com 08-27 10:40:11.782: E/HttpParser(13769): Accept: */* 08-27 10:40:11.782: E/HttpParser(13769): Pragma: no-cache 08-27 10:40:11.782: E/HttpParser(13769): 08-27 10:40:11.782: E/HttpParser(13769): _prebufferFilePath:/mnt/sdcard/ProxyBuffer/files/videorzx201208151345010952759.mp4 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Date: Mon, 27 Aug 2012 02:33:24 GMT 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Server: Apache 08-27 10:40:12.167: E/HttpGetProxy<---(13769): X-Mod-H264-Streaming: version=2.2.7 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Last-Modified: Wed, 15 Aug 2012 06:24:38 GMT 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Accept-Ranges: bytes 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Cache-Control: max-age=315360000 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Expires: Thu, 25 Aug 2022 02:33:24 GMT 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Content-Type: video/mp4 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Powered-By-ChinaCache: HIT from 01006613Y4 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Content-Range: bytes 101901-8311865/8311866 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Content-Length: 8209965 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Age: 408 08-27 10:40:12.167: E/HttpGetProxy<---(13769): Powered-By-ChinaCache: HIT from 01075913r4 08-27 10:40:12.167: E/HttpGetProxy<---(13769): 08-27 10:40:12.172: E/HttpGetProxy(13769): >>>skip:101901 08-27 10:40:12.187: E/HttpParser(13769): Range: bytes=74- 08-27 10:40:12.187: E/HttpParser(13769): Host: video.cztv.com 08-27 10:40:12.187: E/HttpParser(13769): Accept: */* 08-27 10:40:12.187: E/HttpParser(13769): Pragma: no-cache 08-27 10:40:12.187: E/HttpParser(13769): 08-27 10:40:12.187: E/HttpParser(13769): _prebufferFilePath:/mnt/sdcard/ProxyBuffer/files/videorzx201208151345010952759.mp4 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Date: Mon, 27 Aug 2012 02:33:24 GMT 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Server: Apache 08-27 10:40:12.372: E/HttpGetProxy<---(13769): X-Mod-H264-Streaming: version=2.2.7 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Last-Modified: Wed, 15 Aug 2012 06:24:38 GMT 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Accept-Ranges: bytes 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Cache-Control: max-age=315360000 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Expires: Thu, 25 Aug 2022 02:33:24 GMT 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Content-Type: video/mp4 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Powered-By-ChinaCache: HIT from 01006613Y4 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Content-Range: bytes 74-8311865/8311866 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Content-Length: 8311792 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Age: 408 08-27 10:40:12.372: E/HttpGetProxy<---(13769): Powered-By-ChinaCache: HIT from 01075913r4 08-27 10:40:12.372: E/HttpGetProxy<---(13769): 08-27 10:40:12.377: E/HttpGetProxy(13769): >>>skip:74 08-27 10:40:12.537: E/HttpGetProxy-pre->(13769): Range: bytes=1000320- 08-27 10:40:12.537: E/HttpGetProxy-pre->(13769): Host: video.cztv.com 08-27 10:40:12.537: E/HttpGetProxy-pre->(13769): Accept: */* 08-27 10:40:12.537: E/HttpGetProxy-pre->(13769): Pragma: no-cache 08-27 10:40:12.537: E/HttpGetProxy-pre->(13769): 08-27 10:40:12.647: E/MediaPlayer(13769): MediaPlayer::setVideoRect(0,25, 1280, 720) 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Date: Mon, 27 Aug 2012 02:33:24 GMT 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Server: Apache 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): X-Mod-H264-Streaming: version=2.2.7 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Last-Modified: Wed, 15 Aug 2012 06:24:38 GMT 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Accept-Ranges: bytes 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Cache-Control: max-age=315360000 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Expires: Thu, 25 Aug 2022 02:33:24 GMT 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Content-Type: video/mp4 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Powered-By-ChinaCache: HIT from 01006613Y4 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Content-Range: bytes 1000320-8311865/8311866 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Content-Length: 7311546 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Age: 409 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): Powered-By-ChinaCache: HIT from 01075913r4 08-27 10:40:12.962: E/HttpGetProxy ~~~~(13769): 08-27 10:40:14.037: E/testVideoPlayer(13769): 预加载开关:true,等待缓冲时间:8000,首次缓冲时间:3261 本文的源码可以到这里下载：http://download.csdn.net/detail/hellogv/4528270 HttpGetProxy.java源码如下，可以读出大概的运行流程： public class HttpGetProxy{
final static public int SIZE = (int) (3 * 1024 * 1024);
final static public String TAG = "HttpGetProxy";
/** 链接带的端口 */
private int remotePort=-1;
/** 远程服务器地址 */
private String remoteHost;
/** 代理服务器使用的端口 */
private int localPort;
/** 本地服务器地址 */
private String localHost;
private ServerSocket localServer = null;
/** 收发Media Player请求的Socket */
private Socket sckPlayer = null;
/** 收发Media Server请求的Socket */
private Socket sckServer = null;
/**服务器的Address*/
private SocketAddress serverAddress;
/**下载线程*/
private DownloadThread download = null;
/**
* 初始化代理服务器
* @param localport 代理服务器监听的端口
*/
public HttpGetProxy(int localport) {
try {
localPort = localport;
localHost = C.LOCAL_IP_ADDRESS;
localServer = new ServerSocket(localport, 1,InetAddress.getByName(localHost));
} catch (Exception e) {
System.exit(0);
}
}
/**
* 把URL提前下载在SD卡，实现预加载
* @param urlString
* @return 返回预加载文件名
* @throws Exception
*/
public String prebuffer(String urlString,int size) throws Exception{
if(download!=null && download.isDownloading())
download.stopThread(true);
URI tmpURI=new URI(urlString);
String fileName=Utils.urlToFileName(tmpURI.getPath());
String filePath=C.getBufferDir()+"/"+fileName;
download=new DownloadThread(urlString,filePath,size);
download.startThread();
return filePath;
}
/**
* 把网络URL转为本地URL，127.0.0.1替换网络域名
*
* @param url网络URL
* @return [0]:重定向后MP4真正URL，[1]:本地URL
*/
public String[] getLocalURL(String urlString) {
// ----排除HTTP特殊----//
String targetUrl = Utils.getRedirectUrl(urlString);
// ----获取对应本地代理服务器的链接----//
String localUrl = null;
URI originalURI = URI.create(targetUrl);
remoteHost = originalURI.getHost();
if (originalURI.getPort() != -1) {// URL带Port
serverAddress = new InetSocketAddress(remoteHost, originalURI.getPort());// 使用默认端口
remotePort = originalURI.getPort();// 保存端口，中转时替换
localUrl = targetUrl.replace(
remoteHost + ":" + originalURI.getPort(), localHost + ":"
+ localPort);
} else {// URL不带Port
serverAddress = new InetSocketAddress(remoteHost, C.HTTP_PORT);// 使用80端口
remotePort = -1;
localUrl = targetUrl.replace(remoteHost, localHost + ":"
+ localPort);
}
String[] result= new String[]{targetUrl,localUrl};
return result;
}
/**
* 异步启动代理服务器
*
* @throws IOException
*/
public void asynStartProxy() {
new Thread() {
public void run() {
startProxy();
}
}.start();
}
private void startProxy() {
HttpParser httpParser =null;
HttpGetProxyUtils utils=null;
int bytes_read;
byte[] local_request = new byte[1024];
byte[] remote_reply = new byte[1024];
while (true) {
boolean sentResponseHeader = false;
try {// 开始新的request之前关闭过去的Socket
if (sckPlayer != null)
sckPlayer.close();
if (sckServer != null)
sckServer.close();
} catch (IOException e1) {}
try {
// --------------------------------------
// 监听MediaPlayer的请求，MediaPlayer->代理服务器
// --------------------------------------
sckPlayer = localServer.accept();
Log.e(TAG,"------------------------------------------------------------------");
if(download!=null && download.isDownloading())
download.stopThread(false);
httpParser=new HttpParser(remoteHost,remotePort,localHost,localPort);
utils = new HttpGetProxyUtils(sckPlayer,sckServer,serverAddress);
ProxyRequest request = null;
while ((bytes_read = sckPlayer.getInputStream().read(local_request)) != -1) {
byte[] buffer=httpParser.getRequestBody(local_request,bytes_read);
if(buffer!=null){
request=httpParser.getProxyRequest(buffer);
break;
}
}
boolean isExists=new File(request._prebufferFilePath).exists();
if(isExists)
Log.e(TAG,"prebuffer size:"+download.getDownloadedSize());
sckServer = utils.sentToServer(request._body);
// ------------------------------------------------------
// 把网络服务器的反馈发到MediaPlayer，网络服务器->代理服务器->MediaPlayer
// ------------------------------------------------------
while ((bytes_read = sckServer.getInputStream().read(remote_reply)) != -1) {
if(sentResponseHeader){
try{//拖动进度条时，容易在此异常，断开重连
utils.sendToMP(remote_reply,bytes_read);
}catch (Exception e) {
break;//发送异常直接退出while
}
continue;//退出本次while
}
List<byte[]> httpResponse = httpParser.getResponseBody(remote_reply, bytes_read);
if (httpResponse.size() == 0)
continue;//没Header则退出本次循环
sentResponseHeader = true;
String responseStr = new String(httpResponse.get(0));
Log.e(TAG + "<---", responseStr);
//send http header to mediaplayer
utils.sendToMP(httpResponse.get(0));
if (isExists) {//需要发送预加载到MediaPlayer
isExists = false;
int sentBufferSize = 0;
try{
sentBufferSize = utils.sendPrebufferToMP(
request._prebufferFilePath,
request._rangePosition);
}catch(Exception ex){
break;
}
if (sentBufferSize > 0) {// 成功发送预加载，重新发送请求到服务器
int newRange=(int) (sentBufferSize + request._rangePosition);
String newRequestStr = httpParser.modifyRequestRange(request._body,newRange);
Log.e(TAG + "-pre->", newRequestStr);
//修改Range后的Request发送给服务器
sckServer = utils.sentToServer(newRequestStr);
//把服务器的Response的Header去掉
utils.removeResponseHeader(httpParser);
continue;
}
}
// 发送剩余数据
if (httpResponse.size() == 2) {
utils.sendToMP(httpResponse.get(1));
}
}
Log.e(TAG, ".........over..........");
// 关闭 2个SOCKET
sckPlayer.close();
sckServer.close();
} catch (Exception e) {
Log.e(TAG,e.toString());
Log.e(TAG,Utils.getExceptionMessage(e));
}
}
}
声明: 本文由( 张飞不张，文采横飞 )原创编译，转载请保留链接: 玩转 Android MediaPlayer之视频预加载(优化) |
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