How to use ProcessOptionsEncoder.ResumePos

[LAdam-ix]

Hello,
I'm currently using this library in my project, and I have a question regarding the functionality of the ProcessOptionsEncoder.ResumePos property and the whole stop and resuming process.

Here are the specific points I'd like to understand:

1. Is there any other way how to pause an ongoing ProcessWorkerEncoder that runs FFMpegEncoding (created by EncodeFFmpeg()), other than calling Cancel() on it??
2. If I have the process Canceled and have saved the last encoded frame, how can I continue encoding from this frame? Putting it in ProcessOptionsEncoder.ResumePos, when starting the EncodeFFmpeg(), didn't work, and it just started encoding from the beginning.

I'm trying to start Encoding, stop it save the data, and continue even if the app is closed, or just resume it after stoppping.
Can I achieve this functionality with this library, or is it impossible?

Thank you in advance for your assistance.

[mysteryx93]

If you run a FFmpeg process in a command prompt, it just encodes until done. Is there any way to suspend it?

Actually...
https://stackoverflow.com/questions/71257/suspend-process-in-c-sharp

That's an option to explore. You can get the process and call Process.Suspend. I haven't tried it.

ResumePos was designed for Avisynth/VapourSynth encoding.

For FFmpeg, this might work. I'm not sure whether it will be frame-accurate though
https://stackoverflow.com/questions/49846095/how-to-skip-start-frames-with-ffmpeg

ffmpeg will try to adjust accordingly ... not sure whether "try" is reliable. I think it will be most of the times with no guarantee whatsoever.

[mysteryx93]

Also, even for Avisynth and Vapoursynth, generally the start pos has to be within the script itself; so although I don't remember exactly, it's possible that ResumePos was there only to pass to the UI, to inform that it's not a new encode.

[LAdam-ix]

Thank you for your response and the information you gave me.

I have already explored the option of suspending the entire process in C# before discovering this library. However, the methods I came across either didn't work or required too much time to try out at the moment. It's a direction I intend to explore further when I have more time. Still, I also decided to ask here because I had assumed that this library already had this functionality when I saw the ResumePos property.

Regarding FFmpeg, my knowledge is little more than basics, so I will need to look more into it.
Thank you once again for your assistance and suggestions. I will continue to investigate and test to find something that will work.

[mysteryx93]

When using FFmpegSource in Avisynth, doc clearly says

May be frame accurate on good days.

So I would advise you not to rely on that. You'll get into trouble.

Pausing/resuming the process should work.

To get frame-accurate source, one option is to feed an Avisynth script into FFmpeg and read the source file using LSMashSourcee, which is frame-accurate.