\textbf{-frame=pict\_type:} within the chosen specifier indicates the data to be displayed; in this case \textit{pict\_type}, that is, the keyframe type (I, P, B) of the frame under consideration.
-\textbf{input.mkv:} is the media to be analyzed (it can be any container and code).
+\textbf{input.mkv:} is the media to be analyzed (it can be any container and codec).
(see \url{https://ffmpeg.org/ffprobe.html} for more details)
\end{lstlisting}
There are also 2 useful scripts that not only show the keyframe type but also show the GOP length of the media. They are zipped tars with readme's at: \newline
-\small\url{https://cinelerra-gg.org/download/testing/getgop_byDanDennedy.tar.gz} \newline
-\small\url{https://cinelerra-gg.org/download/testing/iframe-probe_byUseSparingly.tar.gz}
+{\small\url{https://cinelerra-gg.org/download/testing/getgop_byDanDennedy.tar.gz}} \newline
+{\small\url{https://cinelerra-gg.org/download/testing/iframe-probe_byUseSparingly.tar.gz}}
We can now look at the timeline of \CGG{} to see the frames that give problems in playback. Using a codec of type Long GOP, it is probably the rare I-frames that give the freezes.
To find a solution you can use MKVToolNix (\url{https://mkvtoolnix.download/}) to correct and insert new keyframes into the mkv file (matroska talks about \textit{cues data}). It can be done even without new encoding. Or you can use the \texttt{Transcode} tool within \CGG{} because during transcoding new keyframes are created that should correct errors.