下面是一个简易的HTML网页示例,其中使用JavaScript读取本地H264文件,并通过canvas元素将其播放到网页上:
<!DOCTYPE html>
<html>
<head>
<title>播放H264文件</title>
</head>
<body>
<canvas id="videoCanvas"></canvas>
<script>
// 创建视频元素
var video = document.createElement('video');
video.autoplay = true;
// 创建画布元素
var canvas = document.getElementById('videoCanvas');
var context = canvas.getContext('2d');
// 读取本地H264文件
function readH264File(file) {
var reader = new FileReader();
reader.onload = function(e) {
playH264File(new Uint8Array(e.target.result));
}
reader.readAsArrayBuffer(file);
}
// 解析并播放H264文件
function playH264File(data) {
var codec = new Module.Codec();
codec.onPictureDecoded = function(y, u, v, width, height) {
context.clearRect(0, 0, canvas.width, canvas.height);
context.drawImage(yuv420ToCanvas(y, u, v, width, height), 0, 0);
codec.decode();
};
codec.init(canvas.width, canvas.height);
for (var i = 0; i < data.length; i++) {
codec.appendFrame(data[i]);
}
codec.decode();
}
// YUV420转换为Canvas图像数据
function yuv420ToCanvas(yData, uData, vData, width , height){
var canvasTmpY = document.createElement("canvas");
var ctxY = canvasTmpY.getContext("2d");
var imageDataY = ctxY.createImageData(width, height);
for (var i=0;i<yData.length;i++)
imageDataY.data[i]=yData[i];
canvasTmpY.width = width;
canvasTmpY.height = height;
ctxY.putImageData(imageDataY,0,0);
var canvasTmpU = document.createElement("canvas");
var ctxU = canvasTmpU.getContext("2d");
var imageDataU = ctxU.createImageData(width / 2, height / 2);
for (var i=0;i<uData.length;i++)
imageDataU.data[i]=uData[i];
canvasTmpU.width = width / 2;
canvasTmpU.height = height / 2;
ctxU.putImageData(imageDataU,0,0);
var canvasTmpV = document.createElement("canvas");
var ctxV = canvasTmpV.getContext("2d");
var imageDataV = ctxV.createImageData(width / 2 , height / 2 );
for (var i=0;i<vData.length;i++)
imageDataV.data[i]=vData[i];
canvasTmpV.width = width / 2 ;
canvasTmpV.height = height / 2 ;
ctxV.putImageData(imageDataV,0,0);
// 将 YUV420 转换为 RGB
yuvToRgb(canvas.width ,canvas.height ,
[canvasTmpY ,canvasTmpU ,canvasTmpV ],
[ctxY ,ctxU ,ctxV ]);
return createRGBImageFrom3Canvas(canvas.width ,canvas.height,
[canvasTmpY ,canvasTmpU ,canvasTmpV ]);
}
function yuvToRgb(width,height,yuvArray,cavansArray){
var tmpArr=[];
for(var j=0;j<height;j++){
for(var i=0;i<width;i++){
var Y = yuvArray[0].getContext("2d").getImageData(i,j,1,1).data[0] -16;
var U = yuvArray[1].getContext("2d").getImageData(i/2,j/2,1,1).data[0] - 128;
var V = yuvArray[2].getContext("2d").getImageData(i/2,j/2,1,1).data[0] - 128;
var R = (Y + 1.402 * V);
var G = (Y - 0.344 * U - 0.714 * V);
var B = (Y + 1.772 * U);
if(R<0)R=0;if(R>255)R=255;
if(G<0)G=0;if(G>255)G=255;
if(B<0)B=0;if(B>255)B=255;
tmpArr.push([parseInt(R),parseInt(G),parseInt(B)]);
}
}
for(var j=0;j<height;j++)
for(var i=0;i<width;i++){
cavansArray.getContext("2d")
.fillStyle="rgb("+tmpArr[i+j*width][0]+","
+tmpArr[i+j*width][1]+","
+tmpArr[i+j*width][2]+")";
cavansArray.getContext("2d")
.fillRect( i ,j , 4 ,4 );
}
}
function createRGBImageFrom3Canvas(width,height,cavansArray){
var canvasTmp = document.createElement("canvas");
var ctxTmp = canvasTmp.getContext('2d');
canvasTmp.width = width ;
canvasTmp.height = height;
var imageDataTmp = ctxTmp.createImageData(width, height);
for (var j=0;j<height;j++){
for(var i=0;i<width;i++){
imageDataTmp.data[4*(i+j*width) ]=cavansArray[0].getContext("2d").getImageData(i,j,1,1).data[0];
imageDataTmp.data[4*(i+j*width)+1]=cavansArray[0].getContext("2d").getImageData(i,j,1,1).data[1];
imageDataTmp.data[4*(i+j*width)+2]=cavansArray[0].getContext("2d").getImageData(i,j,1,1).data[2];
imageDataTmp.data[4*(i+j*width)+3]=255;
}
}
ctxTmp.putImageData(imageDataTmp , 0 , 0 );
return canvasTmp
}
// 监听文件选择事件
document.querySelector('input[type="file"]').addEventListener('change', function(e) {
var file = e.target.files[0];
readH264File(file);
});
</script>
<input type="file" accept=".h264">
</body>
</html>
上述代码创建了一个简单的HTML网页,其中包含一个用于播放视频的画布元素(canvas)和一个用于选择本地H264文件的文件输入(input)。当选择一个H264文件后,通过JavaScript读取该文件,并将其解码并显示在画布上。
请注意,此示例仅用于演示目的,实际上解析和播放H264视频是非常复杂的任务。你可能需要使用现有的H264解码库,如Broadway.js或jsmpeg来处理和播放H264视频流。
内容由零声教学AI助手提供,问题来源于学员提问