ecb0badb
 ming
保存jpg图片
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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>
}
#include <chrono>
#include<string>
using namespace std;
bool bFirstFrame = false;
long last_src_pts = 0;
long last_pts = 0;
void update_pts(AVPacket* pkt) {
if (pkt->pts > 0) {
if (bFirstFrame) {
bFirstFrame = false;
last_src_pts = pkt->pts;
}
int64_t pkt_pts = pkt->pts;
pkt->pts = last_pts + (pkt_pts - last_src_pts);
last_src_pts = pkt_pts;
last_pts = pkt->pts;
pkt->dts = pkt->pts;
}
else {
if (bFirstFrame) {
bFirstFrame = false;
last_pts = 0;
}
pkt->pts = last_pts + 512;
last_pts = pkt->pts;
}
}
void *save_tool(const string uri)
{
AVFormatContext *i_fmt_ctx;
AVCodecContext* codec_ctx = nullptr;
AVCodec *decoder = nullptr;
AVStream *i_video_stream;
int video_index;
AVFormatContext *o_fmt_ctx;
AVStream *o_video_stream;
bool bStop = false;
int frame_nums = 0;
avcodec_register_all();
av_register_all();
avformat_network_init();
/* should set to NULL so that avformat_open_input() allocate a new one */
i_fmt_ctx = NULL;
const char *filename = "2.mp4";
if (avformat_open_input(&i_fmt_ctx, uri.c_str(), NULL, NULL)!=0)
{
fprintf(stderr, " = could not open input file\n");
return nullptr;
}
if (avformat_find_stream_info(i_fmt_ctx, NULL)<0)
{
fprintf(stderr, " = could not find stream info\n");
return nullptr;
}
video_index = av_find_best_stream(i_fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
if (video_index < 0) {
av_log(nullptr, AV_LOG_ERROR, "Cannot find a video stream in the input file ! \n");
return nullptr;
}
codec_ctx = avcodec_alloc_context3(decoder);
if (!codec_ctx){
return nullptr;
}
i_video_stream = i_fmt_ctx->streams[video_index];
if(avcodec_parameters_to_context(codec_ctx, i_video_stream->codecpar) < 0){
return nullptr;
}
avformat_alloc_output_context2(&o_fmt_ctx, NULL, NULL, filename);
o_video_stream = avformat_new_stream(o_fmt_ctx, NULL);
{
AVCodecContext *c;
c = o_video_stream->codec;
c->bit_rate = 400000;
c->codec_id = i_video_stream->codec->codec_id;
c->codec_type = i_video_stream->codec->codec_type;
c->time_base.num = i_video_stream->time_base.num;
c->time_base.den = i_video_stream->time_base.den;
fprintf(stderr, " = time_base.num = %d time_base.den = %d\n", c->time_base.num, c->time_base.den);
c->width = i_video_stream->codec->width;
c->height = i_video_stream->codec->height;
c->pix_fmt = i_video_stream->codec->pix_fmt;
printf(" = width: %d height: %d pix_fmt: %d\n", c->width, c->height, c->pix_fmt);
c->flags = i_video_stream->codec->flags;
c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
c->me_range = i_video_stream->codec->me_range;
c->max_qdiff = i_video_stream->codec->max_qdiff;
c->qmin = i_video_stream->codec->qmin;
c->qmax = i_video_stream->codec->qmax;
c->qcompress = i_video_stream->codec->qcompress;
}
avio_open(&o_fmt_ctx->pb, filename, AVIO_FLAG_WRITE);
avformat_write_header(o_fmt_ctx, NULL);
AVPacket* i_pkt = av_packet_alloc();
av_init_packet(i_pkt);
while (av_read_frame(i_fmt_ctx, i_pkt) >= 0){
update_pts(i_pkt);
static int num = 1;
printf(" = frame %d\n", num++);
av_interleaved_write_frame(o_fmt_ctx, i_pkt);
av_packet_unref(i_pkt);
if(frame_nums > 750){
break;
}
frame_nums++;
}
av_packet_free(&i_pkt);
avformat_close_input(&i_fmt_ctx);
av_write_trailer(o_fmt_ctx);
avcodec_close(o_fmt_ctx->streams[0]->codec);
av_freep(&o_fmt_ctx->streams[0]->codec);
av_freep(&o_fmt_ctx->streams[0]);
avio_close(o_fmt_ctx->pb);
av_free(o_fmt_ctx);
printf("end. \n");
}
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