头文件：
#include <sys/time.h>获取当前时间方法
//当前时间戳 毫秒级别（一秒解多少帧）
long long getNowMs(){
struct timeval tv;
gettimeofday(&tv, NULL);
long long sec = tv.tv_sec%360000; //秒 只取100小时内
long long t = sec*1000+tv.tv_usec/1000;
return t;
}我的手机是 iphone 6s plus 真机测试解码一个 mp4格式102.4 MB的视频：
//打开一个视频文件
+ (void)ffmpegOpenFile:(NSString *)filePath{
// 1 注册组件
// av_register_all();
// 2 初始化网络 如果需要的话
avformat_network_init();
// 初始化 解码器
// avcodec_register_all();
// 3 打开封装格式文件
//封装格式上下文
AVFormatContext *ic = avformat_alloc_context();
//文件路径
const char *url = [filePath UTF8String];
/*
• AVFormatContext **ps 传指针的地址
• const char *url 文件路径（本地的或者网络的http rtsp 地址会被存在AVFormatContext 结构体的 fileName中）
• AVInputFormat *fmt 指定输入的封装格式 一般情况传NULL即可，自行判断即可
• AVDictionary **options 一般传NULL
*/
int re = avformat_open_input(&ic, url, NULL, NULL);
if (re != 0) {
NSLog(@"打开文件失败");
char *error_info = NULL;
av_strerror(re, error_info, 1024);
return;
}
NSLog(@"打开文件成功");
//获取流信息 读取部分视频做探测
re = avformat_find_stream_info(ic, 0);
if (re != 0) {
NSLog(@"avformat_find_stream_info failed!");
}
//总时长，流的信息
NSLog(@"duration =%lld nb_streams = %d",ic->duration,ic->nb_streams);
//打印相关信息
int fps = 0;
int videoStream = 0;
int audioStream = 1;
//(1)遍历
for (int i = 0; i < ic->nb_streams; i++) {
AVStream *as = ic->streams[i];
if (as->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
NSLog(@"VIDEO");
videoStream = i;
fps = r2d(as->avg_frame_rate);
NSLog(@"fps = %d width = %d height = %d codeid = %d pixformat = %d",
fps,
as->codecpar->width,
as->codecpar->height,
as->codecpar->codec_id,
as->codecpar->format);
}
if (as->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
NSLog(@"AUDIO");
audioStream = i;
NSLog(@"sample_rate = %d channels = %d sample_format = %d",
as->codecpar->sample_rate,
as->codecpar->channels,
as->codecpar->format);
}
}
// ====================================
/**
获取音视频流的索引
@param ic#> 上下文 description#>
@param type#> 音频/视频流信息类型 description#>
@param wanted_stream_nb#> 指定取的流的信息（传 -1） description#>
@param related_stream#> 想关流信息（-1） description#>
@param decoder_ret#> 解码器 （NULL） description#>
@param flags#> 暂时无用 description#>
@return <#return value description#>
*/
audioStream = av_find_best_stream(ic, AVMEDIA_TYPE_AUDIO, -1, -1, NULL, 0);
NSLog(@" av_find_best_stream : %d ",audioStream);
//软解码器
AVCodec *codec = avcodec_find_decoder(ic->streams[videoStream]->codecpar->codec_id);
//硬解码
// codec = avcodec_find_decoder_by_name("h264_mediacodec");
if (!codec) {
NSLog(@"avcodec_find_decoder_by_name video failed!");
return ;
}
//解码器初始化
AVCodecContext *vc = avcodec_alloc_context3(codec);
vc->thread_count = 1;
avcodec_parameters_to_context(vc, ic->streams[videoStream]->codecpar);
//打开解码器
re = avcodec_open2(vc,0, 0);
if (re != 0) {
NSLog(@"avcodec_open2 video failed!");
return;
}
////////////////////////////////////////////////////
//音频解码器
AVCodec *acodec = avcodec_find_decoder(ic->streams[audioStream]->codecpar->codec_id);
//硬解码
// codec = avcodec_find_decoder_by_name("h264_mediacodec");
if (!acodec) {
NSLog(@"avcodec_find_decoder_by_name audio failed!");
return ;
}
//解码器初始化
AVCodecContext *ac = avcodec_alloc_context3(acodec);
ac->thread_count = 1;
avcodec_parameters_to_context(ac, ic->streams[audioStream]->codecpar);
//打开解码器
re = avcodec_open2(ac,0, 0);
if (re != 0) {
NSLog(@"avcodec_open2 audio failed!");
return;
}
//读取帧数据
AVPacket *pkt = av_packet_alloc();//创建一个对象空间，初始化
AVFrame *frame = av_frame_alloc();
long long start = getNowMs();
int frameCount = 0;
for (; ; ) {//无线循环
//当时间超过4秒
if (getNowMs() - start >= 3000) {
NSLog(@"now decode fps is %d",frameCount / 3);
start = getNowMs();
frameCount = 0;
}
int re = av_read_frame(ic, pkt);
if (re != 0) {
NSLog(@"读取到结尾处！");
int pos = 3 * r2d(ic->streams[videoStream]->time_base);;
av_seek_frame(ic, videoStream, pos, AVSEEK_FLAG_BACKWARD|AVSEEK_FLAG_FRAME);
continue;
}
//测试音视频解码
AVCodecContext *cc = vc;
if (pkt->stream_index == audioStream) {
cc = ac;
}
//发送的线程中解码
re = avcodec_send_packet(cc, pkt);\
//解码
av_packet_unref(pkt);
if (re != 0) {
NSLog(@"avcodec_send_packet audio failed!");
continue;
}
for (; ; ) {//保证能搜到全部的解码数据
re = avcodec_receive_frame(cc, frame);
if (re != 0) {
// NSLog(@"avcodec_receive_frame audio failed!");
break;
}
// NSLog(@"frame->pts %lld",frame->pts);
if (cc == vc) {
frameCount++;
}
}
//最后一针的时候 avcodec_send_packet(cc, NULL)
av_packet_unref(pkt);
}
//关闭输入的上下文 释放内存
avformat_close_input(&ic);
}
每秒解帧打印 单线程 满cpu负荷 iphone 6s plus
2018-08-02 15:17:57.851324+0800 FFmpeg402[335:43350] now decode fps is 197
2018-08-02 15:18:00.851289+0800 FFmpeg402[335:43350] now decode fps is 272
2018-08-02 15:18:03.854759+0800 FFmpeg402[335:43350] now decode fps is 215
2018-08-02 15:18:06.854035+0800 FFmpeg402[335:43350] now decode fps is 190
软解 每秒解帧打印 超cpu负荷 2线程 iphone 6s plus
2018-08-02 17:10:09.564229+0800 FFmpeg402[393:75064] now decode fps is 291
2018-08-02 17:10:12.564101+0800 FFmpeg402[393:75064] now decode fps is 297
2018-08-02 17:10:15.570074+0800 FFmpeg402[393:75064] now decode fps is 252软解 每秒解帧打印 超cpu负荷 2线程 iphone 7
2018-08-02 17:16:56.167054+0800 FFmpeg402[2023:750470] now decode fps is 307
2018-08-02 17:16:59.167978+0800 FFmpeg402[2023:750470] now decode fps is 433
2018-08-02 17:17:02.170195+0800 FFmpeg402[2023:750470] now decode fps is 321硬件解码 每秒解帧打印 2线程 iphone 6s plus
NSLog(@"codec_id %u",ic->streams[videoStream]->codecpar->codec_id);
AVCodec *codec = avcodec_find_decoder_by_name("h264");
if (!codec) {
NSLog(@"avcodec_find_decoder_by_name video failed!");
return ;
}2018-08-02 17:11:11.934711+0800 FFmpeg402[395:75715] now decode fps is 302
2018-08-02 17:11:14.935176+0800 FFmpeg402[395:75715] now decode fps is 334
2018-08-02 17:11:17.936497+0800 FFmpeg402[395:75715] now decode fps is 247硬件解码 每秒解帧打印 2线程 iphone 7
2018-08-02 17:15:50.380053+0800 FFmpeg402[2021:749772] now decode fps is 352
2018-08-02 17:15:53.380857+0800 FFmpeg402[2021:749772] now decode fps is 455
2018-08-02 17:15:56.391613+0800 FFmpeg402[2021:749772] now decode fps is 354