VideoTools.cpp
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#include "VideoTools.h"
#include "logger.hpp"
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavdevice/avdevice.h>
#include <libavformat/avformat.h>
#include <libavfilter/avfilter.h>
#include <libavutil/avutil.h>
#include <libavutil/pixdesc.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
}
namespace VideoTools {
FFImgInfo* snapshot(const string& uri){
if (uri.empty()){
return nullptr;
}
AVFormatContext* ifmt_ctx = nullptr;
AVCodecContext* codec_ctx = nullptr;
AVCodec* codec = nullptr;
AVPacket* pkt = nullptr;
AVFrame *frame = nullptr;
AVFrame *pFrameRGB = nullptr;
int video_index = -1;
AVStream* st = nullptr;
SwsContext *img_convert_ctx = nullptr;
uint8_t *buffer = nullptr;
int numBytes = 0;
int index = 0;
FFImgInfo* imgInfo = nullptr;
//av_register_all();
avformat_network_init();
// 参数设置
AVDictionary *options = nullptr;
av_dict_set( &options, "bufsize", "655360", 0 );
av_dict_set( &options, "rtsp_transport", "tcp", 0 );
av_dict_set( &options, "stimeout", "30000000", 0 ); // 单位为 百万分之一秒
///打开输入的流
int ret = avformat_open_input(&ifmt_ctx, uri.c_str(), nullptr, &options);
if (ret != 0){
printf("Couldn't open input stream.\n");
goto end_flag ;
}
//查找流信息
if (avformat_find_stream_info(ifmt_ctx, nullptr) < 0){
printf("Couldn't find stream information.\n");
goto end_flag ;
}
//找到视频流索引
video_index = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, nullptr, 0);
st = ifmt_ctx->streams[video_index];
//找到解码器
codec = avcodec_find_decoder(st->codecpar->codec_id);
if (!codec){
fprintf(stderr, "Codec not found\n");
goto end_flag ;
}
//申请AVCodecContext
codec_ctx = avcodec_alloc_context3(codec);
if (!codec_ctx){
goto end_flag ;
}
avcodec_parameters_to_context(codec_ctx, ifmt_ctx->streams[video_index]->codecpar);
//打开解码器
if ((ret = avcodec_open2(codec_ctx, codec, nullptr) < 0)){
goto end_flag ;
}
// 计算解码后原始数据所需缓冲区大小，并分配内存空间 Determine required buffer size and allocate buffer
numBytes = av_image_get_buffer_size(AV_PIX_FMT_BGR24, codec_ctx->width, codec_ctx->height, 1);
buffer = (uint8_t *)av_malloc(numBytes * sizeof(uint8_t));
pFrameRGB = av_frame_alloc();
av_image_fill_arrays(pFrameRGB->data, pFrameRGB->linesize, buffer, AV_PIX_FMT_BGR24, codec_ctx->width, codec_ctx->height, 1);
img_convert_ctx = sws_getContext(codec_ctx->width, codec_ctx->height,codec_ctx->pix_fmt, codec_ctx->width, codec_ctx->height, AV_PIX_FMT_BGR24,
SWS_BICUBIC, nullptr, nullptr, nullptr);
pkt = av_packet_alloc();
frame = av_frame_alloc();
while (av_read_frame(ifmt_ctx, pkt) >= 0){
if (pkt->stream_index == video_index){
int ret = avcodec_send_packet(codec_ctx, pkt);
if (ret >= 0){
ret = avcodec_receive_frame(codec_ctx, frame);
if ((ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) || ret < 0){
LOG_ERROR("Failed to receive frame: {}",ret);
continue;
}
index ++ ;
if (index >= 5){
// 取解码出来的第三帧，应该可以一定程度优化花屏问题
sws_scale(img_convert_ctx, (const unsigned char* const*)frame->data, frame->linesize, 0, codec_ctx->height, pFrameRGB->data, pFrameRGB->linesize);
imgInfo = new FFImgInfo();
imgInfo->pData = buffer;
imgInfo->height = codec_ctx->height;
imgInfo->width = codec_ctx->width;
break;
}
}
}
av_packet_unref(pkt);
}
end_flag:
if (codec_ctx != nullptr){
avcodec_close(codec_ctx);
avcodec_free_context(&codec_ctx);
}
if (ifmt_ctx != nullptr){
avformat_close_input(&ifmt_ctx);
}
if (frame != nullptr){
av_frame_free(&frame);
}
if (pFrameRGB != nullptr){
av_frame_free(&pFrameRGB);
}
if (pkt != nullptr){
av_packet_free(&pkt);
}
return imgInfo;
}
void releaseFFImgInfo(FFImgInfo* info) {
if(nullptr != info){
if(info->pData != nullptr){
av_free(info->pData);
info->pData = nullptr;
}
delete info;
info = nullptr;
}
}
} // namespace