其实具体的代码ffmpeg的官方demo做的功能已经很完善了,自己也就修修补补,下面直接上代码
#include "stdafx.h"
#include <iostream>
#include <stdio.h>
#include <tchar.h>
//这里是个坑,不加extern "C",死活编译不过
extern "C"
{
#include "libavformat/avformat.h"
};
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
AVOutputFormat *ofmt = NULL;
//创建输入AVFormatContext对象和输出AVFormatContext对象
AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
AVPacket pkt;
const char *in_filename;
int ret, i;
int stream_index = 0;
int *stream_mapping = NULL;
int stream_mapping_size = 0;
in_filename = “C:\\test.h264”;
//产生对应的录像文件名
SYSTEMTIME systime;
GetLocalTime(&systime);
char cTime[128];
sprintf(cTime,"%4d/%02d/%02d %02d:%02d:%02d.%03d\n",
systime.wYear,systime.wMonth,systime.wDay,systime.wHour,
systime.wMinute, systime.wSecond,systime.wMilliseconds);
char out_filename[128];
sprintf_s(out_filename,128,"%s.mp4",cTime);
//打开视频文件
if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
//LogMessage::DebugLogInfo("ReCode", "打开视频流失败");
return -1;
}
//获取视频文件信息
if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
//LogMessage::DebugLogInfo("ReCode", "获取视频流信息失败");
return -1;
}
//打印信息
//av_dump_format(ifmt_ctx, 0, in_filename, 0);
//输出文件分配空间
avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
if (!ofmt_ctx) {
//LogMessage::DebugLogInfo("ReCode", "输出文件分配空间分配失败");
return -1;
}
stream_mapping_size = ifmt_ctx->nb_streams;
stream_mapping = (int *)av_mallocz_array(stream_mapping_size, sizeof(*stream_mapping));
if (!stream_mapping) {
//LogMessage::DebugLogInfo("ReCode", "获取mapping失败");
return -1;
}
ofmt = ofmt_ctx->oformat;
for (i = 0; i < ifmt_ctx->nb_streams; i++) {
AVStream *out_stream;
AVStream *in_stream = ifmt_ctx->streams[i];
AVCodecParameters *in_codecpar = in_stream->codecpar;
if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
stream_mapping[i] = -1;
continue;
}
stream_mapping[i] = stream_index++;
out_stream = avformat_new_stream(ofmt_ctx, NULL);
if (!out_stream) {
//fprintf(stderr, "Failed allocating output stream\n");
//LogMessage::DebugLogInfo("ReCode", "分配流对象失败");
return -1;
}
ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
if (ret < 0) {
//LogMessage::DebugLogInfo("ReCode", "拷贝视频code失败");
return -1;
}
out_stream->codecpar->codec_tag = 0;
}
//打开文件
if (!(ofmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
if (ret < 0) {
//LogMessage::DebugLogInfo("ReCode", "打开输出文件失败");
return -1;
}
}
//开始写入文件头
ret = avformat_write_header(ofmt_ctx, NULL);
if (ret < 0) {
//LogMessage::DebugLogInfo("ReCode", "写入文件头失败");
return -1;
}
int m_frame_index = 0;
//开始读取视频流,并获取pkt信息
while (1) {
AVStream *in_stream, *out_stream;
ret = av_read_frame(ifmt_ctx, &pkt);
if (ret < 0)
break;
in_stream = ifmt_ctx->streams[pkt.stream_index];
if (pkt.stream_index >= stream_mapping_size ||
stream_mapping[pkt.stream_index] < 0) {
av_packet_unref(&pkt);
continue;
}
pkt.stream_index = stream_mapping[pkt.stream_index];
out_stream = ofmt_ctx->streams[pkt.stream_index];
//从摄像头直接保存的h264文件,重新编码时得自己加时间戳,不然转换出来的是没有时间的
if(pkt.pts==AV_NOPTS_VALUE){
//Write PTS
AVRational time_base1=in_stream->time_base;
//Duration between 2 frames (us)
int64_t calc_duration=(double)AV_TIME_BASE/av_q2d(in_stream->r_frame_rate);
//Parameters
pkt.pts=(double)(m_frame_index*calc_duration)/(double)(av_q2d(time_base1)*AV_TIME_BASE);
pkt.dts=pkt.pts;
pkt.duration=(double)calc_duration/(double)(av_q2d(time_base1)*AV_TIME_BASE);
}
/* copy packet */
pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
pkt.pos = -1;
ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
if (ret < 0) {
break;
}
av_packet_unref(&pkt);
m_frame_index++;
}
av_write_trailer(ofmt_ctx);
avformat_close_input(&ifmt_ctx);
// close output
if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
avio_closep(&ofmt_ctx->pb);
avformat_free_context(ofmt_ctx);
av_freep(&stream_mapping);
return 0;
}