codec engine代码阅读六---CE_DIR/examples/ti/sdo/ce/examles/apps/video_copy

来源：互联网发布：linux统计行数编辑：程序博客网时间：2024/05/20 05:03

这一篇来看应用，针对于dm6446的apps代码在：apps/video_copy/dualcpu/evmDM6446下面：

apps/video_copy/dualcpu/evmDM6446$ ls
app.c ceapp.c ceapp.cfg in.dat makefile package package.bld package.xdc

里面两个.c文件，一个.cfg文件，两个package.*文件是讨论的重点。
as always,let's have a look at package.xdc, whose content is as the following:

/*!
*  ======== package.xdc ========
*  Codec Engine build support package for the video_copy example.
*
*  This package simply provides a makefile which builds each application.
*/
package ti.sdo.ce.examples.apps.video_copy.dualcpu.evmDM6446 [1, 0, 0] {
}

这里的内容也是只是声明了一个包，其他的什么也没有。然后是package.bld.这里面也没什么内容：

var Pkg = xdc.useModule('xdc.bld.PackageContents');

/* when constructing a release, release everything */
Pkg.attrs.exportAll = true;

Pkg.otherFiles = [
"makefile",
"in.dat",
];

只是提到使用了PackageContents模块，包含两个文件makefile和in.dat.

然后我们来看这里真正的主角ceapp.cfg:

/* use the tracing utility module 使用代码追踪工具模块*/
var TraceUtil = xdc.useModule('ti.sdo.ce.utils.trace.TraceUtil');
//TraceUtil.attrs = TraceUtil.SOCRATES_TRACING;

/* use and configure the osal. 使用并配置osal */
var osalGlobal = xdc.useModule('ti.sdo.ce.osal.Global');
osalGlobal.runtimeEnv = osalGlobal.DSPLINK_LINUX;

/*
*  ======== Engine Configuration CE配置========
*/
var Engine = xdc.useModule('ti.sdo.ce.Engine');//使用engine模块。
var myEngine = Engine.createFromServer(  //从服务器创建引擎
"video_copy",       // Engine name (as referred to in the C app)//指定引擎的名字
"./video_copy.x64P", // path to server exe, relative to its package dir//服务器可执行文件的位置
"ti.sdo.ce.examples.servers.video_copy.evmDM6446" // server package服务器包名
);

有了上述内容,我们就可以使用服务器中的引擎了,然后我们看看app的代码是干什么的,ceapp.c:

int ceapp_init()
{
int status = -1; /* nonzero means failure */

/* initialize Codec Engine runtime first 初始化CE runtime*/
  CERuntime_init();

/* reset, load, and start DSP Engine 复位,加载,启动DSP引擎*/
if ((ceHandle = Engine_open(engineName, NULL, NULL)) == NULL) {
      printf("CEapp-> ERROR: can't open engine %s\n", engineName);
      goto init_end;
}

/* activate DSP trace collection thread */
TraceUtil_start(engineName);

/* allocate and initialize video encoder on the engine在引擎上开辟并初始化视频编译器 */
encHandle = VIDENC_create(ceHandle, encoderName, NULL);
if (encHandle == NULL) {
      printf("CEapp-> ERROR: can't open codec %s\n", encoderName);
      goto init_end;
}

/* allocate and initialize video decoder on the engine在引擎上开辟并初始化视频解码器 */
decHandle = VIDDEC_create(ceHandle, decoderName, NULL);
if (decHandle == NULL) {
      printf("CEapp-> ERROR: can't open codec %s\n", decoderName);
      goto init_end;
}

status = 0;    /* success */

init_end:

return status;
}

这里先对ceapp.c中的代码进行一下总结:
它里面的代码是为app.c调用服务的.里面的函数有这么几个:
ceapp_init()//这是使用引擎的第一步,初始化引擎
ceapp_allocContigBuf 开辟缓冲区,第二步,开辟缓冲区,然后app.c会打开文件,把文件内容一部分一部分地放入缓冲区
ceapp_validateBufSizes验证缓冲区大小时否正确
ceapp_encodeBuf 对缓冲区的内容进行编码
ceapp_decodeBuf 对缓冲区的内容进行解码
ceapp_freeContigBuf 释放缓冲区
ceapp_exit() 关闭引擎

这些函数里面的实现常常会调用IVIDENC,IVIDDEC接口的中的函数.

而这些函数的实现对应都是在codecs中实现的.

下面说app.c了:
简化后的main函数为:

int main(int argc, char *argv[])
{
char *inFileName, *outFileName;

      inFileName  = "in.dat";
      outFileName = "out.dat";
      createInFileIfMissing(inFileName);
   encodeDecodeFile(inFileName, outFileName)
return 0;
}

main函数调用encodeDecodeFile来编解码,简化后的encodeDecodeFile函数为:

static int encodeDecodeFile(char *inFileName, char *outFileName)
{

inFile = fopen(inFileName, "rb")) ;
//打开两个文件,一个用于输入,一个用于输出
outFile = fopen(outFileName, "wb")) ;
ceapp_init();
//初始化引擎
inBuf    = ceapp_allocContigBuf(INFRAMESIZE,    "input data");
//开辟输出缓冲区
encodedBuf = ceapp_allocContigBuf(ENCODEDFRAMESIZE, "encoded data");
//开辟编解缓冲区
outBuf    = ceapp_allocContigBuf(OUTFRAMESIZE,    "output data");
//开辟输出缓冲区
status = ceapp_validateBufSizes(INFRAMESIZE, ENCODEDFRAMESIZE,
//验证编码缓冲区大小是否正常
for (n = 0 ;; n++) {
//for loop,不停地.....
(fread(inBuf, INFRAMESIZE, 1, inFile) == 0) {
//从输入文件读数据到输入缓冲区
status = ceapp_encodeBuf(inBuf,    INFRAMESIZE,
                              encodedBuf, ENCODEDFRAMESIZE);
//将输入缓冲区数据编码后放入编码缓冲区
status = ceapp_decodeBuf(encodedBuf,  ENCODEDFRAMESIZE,
                              outBuf,    OUTFRAMESIZE);
//从编码缓冲区中解码,放入输出缓冲区
fwrite(outBuf, OUTFRAMESIZE, 1, outFile);
//从输出缓冲区写入输出文件
fclose(inFile);
//关闭文件
fclose(outFile);
ceapp_freeContigBuf(inBuf, INFRAMESIZE);
//释放各种缓冲区
ceapp_freeContigBuf(encodedBuf, ENCODEDFRAMESIZE);
ceapp_freeContigBuf(outBuf, OUTFRAMESIZE);
ceapp_exit();
//退出引擎
return status;
//返回
}

本篇说完总的工作流程就差不多了解了,接下来将会结合文档,说具体代码细节,并做一些示例程序.

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