ffmpeg入门之Windows开发之二（视频转码）

添加ffmpeg windows编译安装及入门指南-CSDN博客?的头文件和依赖库如下：

main 函数如下：

extern "C"
{
#ifdef __cplusplus
#define __STDC_CONSTANT_MACROS

#endif

}
extern "C" {

#include <libavutil/timestamp.h>
#include <libavformat/avformat.h>
#include <libavutil/mem.h>

}

static void log_packet(const AVFormatContext* fmt_ctx, const AVPacket* pkt, const char* tag)
{
?? ?AVRational* time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;

?? ?/*printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
?? ??? ?tag,
?? ??? ?av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
?? ??? ?av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
?? ??? ?av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
?? ??? ?pkt->stream_index);*/
}

int main()
{
?? ?AVOutputFormat* ofmt = NULL;
?? ?AVFormatContext* ifmt_ctx = NULL, * ofmt_ctx = NULL;
?? ?AVPacket pkt;
?? ?const char* in_filename, * out_filename;
?? ?int ret;
?? ?unsigned int ?i;
?? ?int stream_index = 0;
?? ?int* stream_mapping = NULL;
?? ?int stream_mapping_size = 0;

?? ?/*if (argc < 3) {
?? ??? ?printf("usage: %s input output\n"
?? ??? ??? ?"API example program to remux a media file with libavformat and libavcodec.\n"
?? ??? ??? ?"The output format is guessed according to the file extension.\n"
?? ??? ??? ?"\n", argv[0]);
?? ??? ?return 1;
?? ?}*/

?? ?in_filename = "../resources/video.avi";
?? ?out_filename = "../resources/video.mp4";

?? ?if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
?? ??? ?fprintf(stderr, "Could not open input file '%s'", in_filename);
?? ??? ?goto end;
?? ?}

?? ?if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
?? ??? ?fprintf(stderr, "Failed to retrieve input stream information");
?? ??? ?goto end;
?? ?}

?? ?av_dump_format(ifmt_ctx, 0, in_filename, 0);

?? ?avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
?? ?if (!ofmt_ctx) {
?? ??? ?fprintf(stderr, "Could not create output context\n");
?? ??? ?ret = AVERROR_UNKNOWN;
?? ??? ?goto end;
?? ?}

?? ?stream_mapping_size = ifmt_ctx->nb_streams;
?? ?stream_mapping = (int*)av_malloc_array(stream_mapping_size, sizeof(*stream_mapping));
?? ?if (!stream_mapping) {
?? ??? ?ret = AVERROR(ENOMEM);
?? ??? ?goto end;
?? ?}

?? ?ofmt = (AVOutputFormat * )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");
?? ??? ??? ?ret = AVERROR_UNKNOWN;
?? ??? ??? ?goto end;
?? ??? ?}

?? ??? ?ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
?? ??? ?if (ret < 0) {
?? ??? ??? ?fprintf(stderr, "Failed to copy codec parameters\n");
?? ??? ??? ?goto end;
?? ??? ?}
?? ??? ?out_stream->codecpar->codec_tag = 0;
?? ?}
?? ?av_dump_format(ofmt_ctx, 0, out_filename, 1);

?? ?if (!(ofmt->flags & AVFMT_NOFILE)) {
?? ??? ?ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
?? ??? ?if (ret < 0) {
?? ??? ??? ?fprintf(stderr, "Could not open output file '%s'", out_filename);
?? ??? ??? ?goto end;
?? ??? ?}
?? ?}

?? ?ret = avformat_write_header(ofmt_ctx, NULL);
?? ?if (ret < 0) {
?? ??? ?fprintf(stderr, "Error occurred when opening output file\n");
?? ??? ?goto end;
?? ?}

?? ?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];
?? ??? ?log_packet(ifmt_ctx, &pkt, "in");

?? ??? ?/* 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;
?? ??? ?log_packet(ofmt_ctx, &pkt, "out");

?? ??? ?ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
?? ??? ?if (ret < 0) {
?? ??? ??? ?fprintf(stderr, "Error muxing packet\n");
?? ??? ??? ?break;
?? ??? ?}
?? ??? ?av_packet_unref(&pkt);
?? ?}

?? ?av_write_trailer(ofmt_ctx);
end:

?? ?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);

?? ?if (ret < 0 && ret != AVERROR_EOF) {
?? ??? ?//fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
?? ??? ?return 1;
?? ?}
?? ?system("pause");
?? ?return 0;
}

最后video.avi的格式转换为output.avi文件。

源码下载：

链接：https://pan.baidu.com/s/1ygX8kTARSfyrEhlZMULY4A?
提取码：0vg7?

文章参考：

ffmpeg入门教程之Windows开发环境搭建_windows pkg-config --cflags -- libavformat libavco-CSDN博客?缺的库下载参考?：

ffmpeg5.0+h264+h265 windows下编译方法_ffmpeg 5.0 win10 dll 编译-CSDN博客