ffmpeg av_seek_frame

int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags);

#include <libavformat/avformat.h>

int main(int argc, char *argv[]) {
    AVFormatContext *fmt_ctx = NULL;
    int ret;

    // 打开媒体文件
    if ((ret = avformat_open_input(&fmt_ctx, "input.mp4", NULL, NULL)) < 0) {
        fprintf(stderr, "Could not open input file.\n");
        return ret;
    }

    // 寻找媒体文件中的流信息
    if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
        fprintf(stderr, "Failed to retrieve input stream information.\n");
        avformat_close_input(&fmt_ctx);
        return ret;
    }

    // 寻找视频流的索引
    int video_stream_index = -1;
    for (int i = 0; i < fmt_ctx->nb_streams; i++) {
        if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            video_stream_index = i;
            break;
        }
    }

    if (video_stream_index == -1) {
        fprintf(stderr, "Failed to find a video stream.\n");
        avformat_close_input(&fmt_ctx);
        return -1;
    }

    // 寻找距离10秒处最近的关键帧
    int64_t timestamp = 10 * AV_TIME_BASE;  // 10 seconds
    ret = av_seek_frame(fmt_ctx, video_stream_index, timestamp, AVSEEK_FLAG_BACKWARD);
    if (ret < 0) {
        fprintf(stderr, "Failed to seek to position.\n");
    } else {
        printf("Seek successful.\n");
    }

    // 清理
    avformat_close_input(&fmt_ctx);
    return 0;
}