Problems using ESP-EYE and base64

[Luiz.Picolo]

So, I'm doing a project and I need to turn an image into base64, but I do not know how to continue from here. I managed to make it work with text, but I could not with image.

I'm using the esp-eye and the crypto / base64.h file.

Code: [Select all] [Expand/Collapse]

1.   camera_fb_t * pic = NULL;
2.   pic = esp_camera_fb_get();
3.  
4.   size_t pic_len;
5.   pic_len = pic->len;
6.  
7.   char size[50];
8.   char img[100]="test";
9.  
10.   sprintf(size,"%zu",pic_len);
11.  
12.   esp_camera_fb_return(pic);
13.  
14.   size_t output_length; // note *NOT* a pointer
15.   char * encoded = base64_encode((const unsigned char *)img, strlen(size), &output_length);
16.  
17.   printf(encoded);

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Can someone help me with this code?
Or find another way to make it work?

[ESP_Sprite]

Please take a long, hard look at what you actually feed into the base64 encoder in the 'size' argument.

[Luiz.Picolo]

This is the problem, I can not understand what to put there, I need help from someone who has more understanding about it.

[ESP_Sprite]

Sure you can, just think methodologically.

- What do you think the base64_encode function wants to see in the 'len' argument? The length of what? In what units?
- What does pic_len contain exactly?
- If you use sprintf to convert the value of pic_len to a string and put it in the 'size' variable, what does 'size' contain?
- What does strlen() do?
- What does strlen(size) give as a result?
- From that, why does a base64-encode of "test" work, but one of the picture does not?

[Luiz.Picolo]

-The base64_encode wants to see the number of bytes the data has
-I guess that is the number of bytes of the photo taken by the camera
-The number of bytes converted to char
-Returns the length of the string
-The length of the char variable
-I still do not know

To be easier to understand my problem, here is the rest of my code!
Now I'm having some problems on "printf (*encoded);"

Code: [Select all] [Expand/Collapse]

1. #include "app_camera.h"
2. #include "app_wifi.h"
3. //#include "app_httpd.h"
4. #include "app_httpd.h"
5. #include "esp_timer.h"
6. #include "img_converters.h"
7. #include "fb_gfx.h"
8. #include "sdkconfig.h"
9. #include "esp_log.h"
10.  
11. #include "wpa/includes.h"
12. #include "os.h"
13. #include "wpa2/utils/base64.h"
14.  
15. #include <stdio.h>
16. #include <string.h>
17. #include <unistd.h>
18.  
19. static const char *TAG = "Teste";
20.  
21. static void periodic_timer_callback(void *arg);
22.  
23. void app_main()
24. {
25. //app_wifi_main();
26. app_camera_main();
27. //app_httpd_main();
28. usleep(10000000);
29. const esp_timer_create_args_t periodic_timer_args = {
30. .callback = &periodic_timer_callback,
31. .name = "periodic"};
32.  
33. esp_timer_handle_t periodic_timer;
34. ESP_ERROR_CHECK(esp_timer_create(&periodic_timer_args, &periodic_timer));
35. /* The timer has been created but is not running yet */
36.  
37. /* Start the timers */
38. ESP_ERROR_CHECK(esp_timer_start_periodic(periodic_timer, 10000000)); //Time of the pic
39. ESP_LOGI(TAG, "Started timer");
40. }
41.  
42. static void periodic_timer_callback(void *arg) //Pic
43. {
44. camera_fb_t * pic = NULL;
45. pic = esp_camera_fb_get();
46. size_t pic_len;
47. pic_len = pic->len;
48. esp_camera_fb_return(pic);
49. size_t output_length; // note *NOT* a pointer
50. unsigned char * encoded = base64_encode((const unsigned char *)pic->buf, pic_len, &output_length);
51. printf (*encoded);
52.  
53. ESP_LOGI(TAG, "10 seconds");
54. }

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[ESP_Sprite]

Seems you have at least found your logic error in your first post. I think the error you have now is one of ownership. esp_camera_fb_return is a function you're supposed to do if you're entirely done with the memory that esp_camera_fb_get gives you; you're effectively done parsing the camera image and tell the camera API that it can re-use the memory. Is that true in your code?

[Luiz.Picolo]

It's working, I've modified the memory release and data output. now it's working 100%
Thank you for your help!

Code: [Select all] [Expand/Collapse]

1. #include "app_camera.h"
2. #include "app_wifi.h"
3. #include "app_httpd.h"
4. #include "esp_timer.h"
5. #include "img_converters.h"
6. #include "fb_gfx.h"
7. #include "sdkconfig.h"
8. #include "esp_log.h"
9.  
10. #include "wpa/includes.h"
11. #include "os.h"
12. #include "wpa2/utils/base64.h"
13.  
14. #include <stdio.h>
15. #include <string.h>
16. #include <unistd.h>
17.  
18. static const char *TAG = "Teste";
19.  
20. static void periodic_timer_callback(void *arg);
21.  
22. void app_main()
23. {
24.     //app_wifi_main();
25.     app_camera_main();
26.     //app_httpd_main();
27.     usleep(10000000);
28.     const esp_timer_create_args_t periodic_timer_args = {
29.         .callback = &periodic_timer_callback,
30.         .name = "periodic"};
31.  
32.     esp_timer_handle_t periodic_timer;
33.     ESP_ERROR_CHECK(esp_timer_create(&periodic_timer_args, &periodic_timer));
34.     /* The timer has been created but is not running yet */
35.  
36.     /* Start the timers */
37.     ESP_ERROR_CHECK(esp_timer_start_periodic(periodic_timer, 10000000)); //Time of the pic
38.     ESP_LOGI(TAG, "Started timer");
39. }
40.  
41. static void periodic_timer_callback(void *arg) //Pic
42. {
43.   camera_fb_t * pic = NULL;
44.   pic = esp_camera_fb_get();
45.  
46.   size_t pic_len;
47.   pic_len = pic->len;
48.  
49.  
50.   size_t output_length; // note *NOT* a pointer
51.   unsigned char * encoded = base64_encode((const unsigned char *)pic->buf, pic_len, &output_length);
52.  
53.   printf("%.*s", output_length, encoded);
54.   free(encoded);
55.   esp_camera_fb_return(pic);
56.  
57.   ESP_LOGI(TAG, "10 seconds");
58. }

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