TRichView.com

Do you use FFmpeg?
What version?
Does it happen on all RTSP streams?

What's the problem exactly?

(maybe it's an Uniscribe issue? Try assigning RVStyle.TextEngine = rvteWindows)

If the error text is shown on TRichView itself, this mean that an exception happens while drawing content.
Most probably. it happens because TRichView is not formatted.
Do not forget to call Format after loading.

Unfortunately, I can help only if I will be able to reproduce this problem.

Do you have TRVStyle linked only to this TRichView? If the same TRVStyle is linked with 2 or more TRichView, one of them can change styles in it, and others will be out of sync.

1) TRichView saves these bullets to RTF as simple pictures.
I do not remember what this solution was chosen instead of RTF's bullet-pictures. Most probably, MS Word resizes bullet-pictures in an uncontrollable way, and results do not look good for most pictures.
This is the reason why this list ...

It is intentional. TRIchViewEdit mimics TEdit and TMemo behavior. They, as I understand it, mimic the behavior of standard editors for the platform.

It looks like this is a bug.
Open fmxRVSelectionHandlesFM.pas, and change procedure TRVFMXSelectionHandles.Clear to:

procedure TRVFMXSelectionHandles.Clear;
begin
FLeftSelPt := nil;
FRightSelPt := nil;
FCaretPt := nil;
end;

Then recompile the packages (run "Install TRichView FMX in Delphi IDE ...

This exception happens in try..except block, and finally LoadRTF function simply returns False.
The exception is not noticeable unless debugging in Delhi IDE.

The correct way to change zooming is assigning DocumentPixelsPerInch property (in VCL and Lazarus versions)

The values in this table are indexes of initial styles. These styles are added to TRVStyle.TextStyles by default, but you can add and delete them.

While editing (including insertion from a file or the clipboard), new styles can be added. Editing operation do not delete styles, but they can add new ...

I also noticed that your using of the \u# for unicode chars does not have the fallback char in it, like "\u123456 ?". I thought that fallback char was mandatory.
Fallback chars are optional. If you need them, include rvrtfDuplicateUnicode in RTFOptions property.
These characters are useful if this ...

This is a TRichView bug.
It appears that SimpleConcateSubitems processes each item in table cells twice (when calling MassSimpleConcate, and directly in SimpleConcateSubitems). As a result, the number of calls grows exponentially depending on the table nesting level.
When table nesting level is not ...

TRichView uses format strings with "%s" placeholders for list text (RVStyles.ListStyles[].Levels[].FormatString).
However, it is expected that "%s" placeholders are used only in FormatStrings for numbered list types (like decimal, Roman, etc.), not for bullets.
So, for bullets, TRichView saves ...

OnClick means clicking on control, and TRichView has the default behavior inherited from TControl.
I suggest using other mouse events instead.

Yes, the idea is generally correct.

Some notes:

1. Your code does not work if the hyperlink is in a table cell.
(the "current" methods work for cells, but not methods that use item indexes)
To fix, instead of RichViewEdit1, use RichViewEdit1.TopLevelEditor.

2. When finding a range of the link's ...