Loop Recording Not Deleting or Overwriting Old Files With RTC-Based Filenames

FreeRTOS SDK
1

Hi all,

I’m using the Ameba Pro2 SDK with MP4 loop recording. My setup works fine with static filenames, but when I dynamically generate filenames using RTC timestamps, loop deletion/overwrite stops working.

Setup:

  • Loop mode enabled: mm_module_ctrl(mp4_ctx, CMD_MP4_LOOP_MODE, 1);

  • Number of files: record_file_num = 5

  • Recording length: 30 seconds per file

  • Audio format: AAC (mp4_audio_format = AUDIO_AAC)

  • File names dynamically set with RTC in mp4_stop_cb() callbackstatic void set_mp4_filename_with_rtc(void)
    {
    time_t seconds = rtc_read();
    struct tm *timeinfo = localtime(&seconds);
    char filename[32];
    snprintf(filename, sizeof(filename), “NuraEye_%04d%02d%02d_%02d%02d%02d”,
    timeinfo->tm_year + 1900,
    timeinfo->tm_mon + 1,
    timeinfo->tm_mday,
    timeinfo->tm_hour,
    timeinfo->tm_min,
    timeinfo->tm_sec);
    snprintf(mp4_v1_params.record_file_name,
    sizeof(mp4_v1_params.record_file_name),
    “%s”, filename);
    mm_module_ctrl(mp4_ctx, CMD_MP4_SET_RECORD_FILE_NAME,
    (int)mp4_v1_params.record_file_name);
    }

    int mp4_stop_cb(void *parm)
    {
    printf(“-----Record stop------\r\n”);
    set_mp4_filename_with_rtc();
    return 0;
    }

  • MP4 Start / Loop Settings: set_mp4_filename_with_rtc(); // set filename using RTC
    mm_module_ctrl(mp4_ctx, CMD_MP4_SET_PARAMS, (int)&mp4_v1_params);
    mm_module_ctrl(mp4_ctx, CMD_MP4_SET_STOP_CB, (int)mp4_stop_cb);
    mm_module_ctrl(mp4_ctx, CMD_MP4_SET_END_CB, (int)mp4_end_cb);
    mm_module_ctrl(mp4_ctx, CMD_MP4_LOOP_MODE, 1); // Enable loop mode
    mm_module_ctrl(mp4_ctx, CMD_MP4_START, mp4_v1_params.record_file_num);

  • Issue Observed:

    • Loop index cycles correctly (0 → 4 → 0 → …), but old files are never deleted or overwritten.

    • With static filenames, loop deletion works perfectly.

    • The SDK’s loop deletion logic depends on fixed filenames. When filenames change dynamically (RTC-based), the SDK treats each file as new, so no overwrite occurs.

    Is there a built-in way in the SDK to use RTC-based filenames while keeping loop deletion/overwrite active, or is the manual workaround the only approach…?

Thanks in advance for any guidance!

2

Hi @ravinder

The MP4 module does not support deleting files when the MP4 filenames are different.
This feature has to be implemented manually. You may refer to the ff.h to use the API.

3

Hi @pammyleong,

Thank you for the clarification and the reference. I’ll handle the deletion manually using the ff.h APIs as suggested. Appreciate your help!