error ‘GST_BUFFER_SIZE’ was not declared in this scope

This error message is indicating that the identifier "GST_BUFFER_SIZE" is not recognized in the current scope. This typically occurs when the variable or constant has not been declared or is not accessible in the current context.

To fix this error, you can try the following steps:

1. Check if you have included the necessary header file that contains the declaration of "GST_BUFFER_SIZE". Make sure to include the correct header file that defines this constant.

2. Verify that the variable or constant "GST_BUFFER_SIZE" is declared in the appropriate scope before it is used. If it is defined in a different file or function, ensure that it is properly declared or imported in the current scope.

3. Check for any typographical errors in the spelling or capitalization of "GST_BUFFER_SIZE". Ensure that the identifier is spelled correctly and matches the declaration exactly.

If none of these steps resolve the issue, it may be necessary to provide more context or code snippets to further diagnose the problem.