author ： Empty bad uncle
Blog ：https://xuhss.com

The breakfast shop won't be open till night , The people who want to eat have already come ！

Finish opening in the extension library ffmpeg decoder

One 、 Add decoder context member variables

XFFmpeg.h Add member variables

 Decoder context ：AVCodecContext *vcodec

add to Close function For release Context ：

 void Close();

The complete code is as follows

#pragma once
struct AVFormatContext;
struct AVPacket;
struct AVCodecContext;
class XFFmpeg
{
public:
// Open the video
bool Open(const char *url);
// Read a burst of video Store... Internally
bool Read();
void Close();
XFFmpeg();
~XFFmpeg();
int totalms = 0;
protected:
// Unpack context
AVFormatContext *ic = 0;
// Read video frames
AVPacket *pkt = 0;
// Decoder context
AVCodecContext *vcodec = 0;
};

Two 、 Allocate decoder and complete decoder related memory release

XFFmpeg.cpp add to open and close Implementation of function

open Implementation of function

bool XFFmpeg::Open(const char *url)
{

printf("XFFmpeg::open %s\n", url);
// Open the video decapsulation 
int re =avformat_open_input(&ic, url, 0, 0);
if (re != 0)
{

char buf[1024] = {
 0 };
av_strerror(re, buf, 1023);
printf("avformat open fail:%s\n", buf);
return false;
}
// Get stream 
avformat_find_stream_info(ic, 0);
// Total duration of video acquisition 
this->totalms = ic->duration / (AV_TIME_BASE / 1000);
printf("Total Ms =%d\n", totalms);
// Turn on the decoder 0 video 1 Audio 
AVCodecParameters *para = ic->streams[0]->codecpar;
// Find the decoder 
AVCodec * codec = avcodec_find_decoder(para->codec_id);
if (!codec)
{

printf("avcodec_find_decoder %d failed!\n", para->codec_id);
}
// Assign decoder context 
vcodec = avcodec_alloc_context3(codec);
// Configure decoder context 
avcodec_parameters_to_context(vcodec, para);
// Multithreading decoding 
vcodec->thread_count = 8;
// Open context 
re = avcodec_open2(vcodec, 0, 0);
if (re != 0)
{

avcodec_free_context(&vcodec);
char buf[1024];
av_strerror(re, buf, sizeof(buf) - 1);
printf("avcodec_open2 failec:%s!\n", buf);
}
printf("avcodec_open2 successed \n");
return true;
}

Close Function implementation that ：

void XFFmpeg::Close()
{

printf("XFFmpeg::Close\n");
if (ic)
{

avformat_close_input(&ic);
}
if (vcodec)
{

avcodec_free_context(&vcodec);
}
if (pkt)
{

av_packet_free(&pkt);
}
}

The complete code is as follows

#include "XFFmpeg.h"
#include <stdio.h>
extern "C" {

#include "libavformat\avformat.h"
}
void XFFmpeg::Close()
{

printf("XFFmpeg::Close\n");
if (ic)
{

avformat_close_input(&ic);
}
if (vcodec)
{

avcodec_free_context(&vcodec);
}
if (pkt)
{

av_packet_free(&pkt);
}
}
bool XFFmpeg::Open(const char *url)
{

printf("XFFmpeg::open %s\n", url);
// Open the video decapsulation 
int re =avformat_open_input(&ic, url, 0, 0);
if (re != 0)
{

char buf[1024] = {
 0 };
av_strerror(re, buf, 1023);
printf("avformat open fail:%s\n", buf);
return false;
}
// Get stream 
avformat_find_stream_info(ic, 0);
// Total duration of video acquisition 
this->totalms = ic->duration / (AV_TIME_BASE / 1000);
printf("Total Ms =%d\n", totalms);
// Turn on the decoder 0 video 1 Audio 
AVCodecParameters *para = ic->streams[0]->codecpar;
// Find the decoder 
AVCodec * codec = avcodec_find_decoder(para->codec_id);
if (!codec)
{

printf("avcodec_find_decoder %d failed!\n", para->codec_id);
}
// Assign decoder context 
vcodec = avcodec_alloc_context3(codec);
// Configure decoder context 
avcodec_parameters_to_context(vcodec, para);
// Multithreading decoding 
vcodec->thread_count = 8;
// Open context 
re = avcodec_open2(vcodec, 0, 0);
if (re != 0)
{

avcodec_free_context(&vcodec);
char buf[1024];
av_strerror(re, buf, sizeof(buf) - 1);
printf("avcodec_open2 failec:%s!\n", buf);
}
printf("avcodec_open2 successed \n");
return true;
}
bool XFFmpeg::Read()
{

if (!ic)
return false;
// Storage space of video frames 
if (!pkt)
{

// Allocate object space 
pkt = av_packet_alloc();
}
else
{

// Reference count -1 Clean up video frames 
av_packet_unref(pkt);
}
int re = 0;
bool isFindVideo = false;
// Audio data lost 
for (int i = 0; i < 20; i++)
{

// Read a frame of data 
re = av_read_frame(ic, pkt);
// Read failed or read to the end of the file 
if (re != 0)
{

return false;
}
// Is it a video frame 
if (pkt->stream_index == 0)
{

isFindVideo = true;
break;
}
// Audio frame clear packet
av_packet_unref(pkt);
}
return isFindVideo;
}
XFFmpeg::XFFmpeg()
{

printf("Create XFFmpeg\n");
}
XFFmpeg::~XFFmpeg()
{

printf("Delete XFFmpeg\n");
}

PyFFmpeg.cpp Add Close Function call ：

void PyFFmpeg::Close(PyFFmpeg*self)
{

printf("PyFFmpeg::Close\n");
self->ff->Close();
delete self->ff;
Py_TYPE(self)->tp_free(self);
}

After operation , You'll find that , Decoder context loaded successfully

3、 ... and 、 summary

• This article completes opening in the extension library ffmpeg decoder .
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