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  • Text recognition from each frame of long Video Stream [closed]

    19 mars 2020, par Shashikant Sharma

    I am a naive android app developer who comes from reactJS background and it’s my First project in android. I have a requirement to develop an android app that needs to capture all of time intervals at which a particular text appears in the video stream. Actually I am not able to find the approach in order to proceed for the app development. I know it sounds stupid to post such a question on such portal but I am not asking for any source code or link to GitHub repo.
    (NOTE : Video stream would be 30min+ log and Text that needs to be recognized would appear at a fixed position in the video).

  • How can I develop Image recognition program

    18 juillet 2017, par SeongHyun Lee

    My program will recognize the advertisement between each TV Programs.
    But I don’t know how to recognize the ads.
    I had Sound Recognition in mind but It’s so difficult.
    I’m using FFmpeg Library.
    There is VideoState struct Reference.

    typedef struct VideoState {
    SDL_Thread *read_tid;
    SDL_Thread *video_tid;
    SDL_Thread *refresh_tid;
    AVInputFormat *iformat;
    int no_background;
    int abort_request;
    int force_refresh;
    int paused;
    int last_paused;
    int que_attachments_req;
    int seek_req;
    int seek_flags;
    int64_t seek_pos;
    int64_t seek_rel;
    int read_pause_return;
    AVFormatContext *ic;

    int audio_stream;

    int av_sync_type;
    double external_clock; /* external clock base */
    int64_t external_clock_time;

    double audio_clock;
    double audio_diff_cum; /* used for AV difference average computation */
    double audio_diff_avg_coef;
    double audio_diff_threshold;
    int audio_diff_avg_count;
    AVStream *audio_st;
    PacketQueue audioq;
    int audio_hw_buf_size;
    DECLARE_ALIGNED(16,uint8_t,audio_buf2)[AVCODEC_MAX_AUDIO_FRAME_SIZE * 4];
    uint8_t silence_buf[SDL_AUDIO_BUFFER_SIZE];
    uint8_t *audio_buf;
    uint8_t *audio_buf1;
    unsigned int audio_buf_size; /* in bytes */
    int audio_buf_index; /* in bytes */
    int audio_write_buf_size;
    AVPacket audio_pkt_temp;
    AVPacket audio_pkt;
    struct AudioParams audio_src;
    struct AudioParams audio_tgt;
    struct SwrContext *swr_ctx;
    double audio_current_pts;
    double audio_current_pts_drift;
    int frame_drops_early;
    int frame_drops_late;
    AVFrame *frame;

    enum ShowMode {
       SHOW_MODE_NONE = -1, SHOW_MODE_VIDEO = 0, SHOW_MODE_WAVES,
    SHOW_MODE_RDFT, SHOW_MODE_NB
    } show_mode;
    int16_t sample_array[SAMPLE_ARRAY_SIZE];
    int sample_array_index;
    int last_i_start;
    RDFTContext *rdft;
    int rdft_bits;
    FFTSample *rdft_data;
    int xpos;

    SDL_Thread *subtitle_tid;
    int subtitle_stream;
    int subtitle_stream_changed;
    AVStream *subtitle_st;
    PacketQueue subtitleq;
    SubPicture subpq[SUBPICTURE_QUEUE_SIZE];
    int subpq_size, subpq_rindex, subpq_windex;
    SDL_mutex *subpq_mutex;
    SDL_cond *subpq_cond;

    double frame_timer;
    double frame_last_pts;
    double frame_last_duration;
    double frame_last_dropped_pts;
    double frame_last_returned_time;
    double frame_last_filter_delay;
    int64_t frame_last_dropped_pos;
    double video_clock;                          ///< pts of last decoded frame
    / predicted pts of next decoded frame
    int video_stream;
    AVStream *video_st;
    PacketQueue videoq;
    double video_current_pts;                    ///< current displayed pts
    (different from video_clock if frame fifos are used)
    double video_current_pts_drift;              ///< video_current_pts - time
    (av_gettime) at which we updated video_current_pts - used to have running
    video pts
    int64_t video_current_pos;                   ///< current displayed file pos
    VideoPicture pictq[VIDEO_PICTURE_QUEUE_SIZE];
    int pictq_size, pictq_rindex, pictq_windex;
    SDL_mutex *pictq_mutex;
    SDL_cond *pictq_cond;
    #if !CONFIG_AVFILTER
    struct SwsContext *img_convert_ctx;
    #endif

    char filename[1024];
    int width, height, xleft, ytop;
    int step;

    #if CONFIG_AVFILTER
    AVFilterContext *in_video_filter;           ///< the first filter in the
    video chain
    AVFilterContext *out_video_filter;          ///< the last filter in the
    video chain
    int use_dr1;
    FrameBuffer *buffer_pool;
    #endif

    int refresh;
    int last_video_stream, last_audio_stream, last_subtitle_stream;

    SDL_cond *continue_read_thread;

    enum V_Show_Mode v_show_mode;
    } VideoState;

    What can I use for My Program.... I really need your help.. Thank you !!!

  • Encountered problems when trying to run the code of article "Compressed Video Action Recognition", beginner, need some guidance, thanks a lot

    27 décembre 2018, par Wonderful

    Here is the problem I encountered.
    enter image description here