What causes "Error while capturing frames with FFmpeg." in NickeManarin/ScreenToGif?

Read the exception's HelpLink which contains the FFmpeg command and stderr output — this pinpoints the exact FFmpeg error.

NickeManarin/ScreenToGif · error · Exception

Error while capturing frames with FFmpeg.

Error message

Error while capturing frames with FFmpeg.

What it means

Thrown by VideoSourceViewModel after an FFmpeg process exits with non-empty StandardError output. The method starts FFmpeg to extract frames from a video, awaits its exit, then checks if error text was written. If so, it throws with the FFmpeg command arguments and error output embedded in the exception's HelpLink.

Source

Thrown at ScreenToGif.ViewModel/VideoSourceViewModel.cs:768

                    if (Math.Abs(current - FrameCount) < double.Epsilon)
                        GetFiles(folder);
                }
            };
            
            _process.StartInfo = info;
            _process.Start();
            _process.BeginOutputReadLine();
            _process.BeginErrorReadLine();
            
            await _process.WaitForExitAsync();

            if (_process == null)
                return;

            var error = await _process?.StandardError?.ReadToEndAsync();

            if (!string.IsNullOrWhiteSpace(error))
                throw new Exception("Error while capturing frames with FFmpeg.") { HelpLink = $"Command:\n\r{info.Arguments}\n\rResult:\n\r{error}" };
        }
        catch (Exception e)
        {
            LogWriter.Log(e, "Error importing frames with FFmpeg");

            IsImporting = false;

            Dispatcher.CurrentDispatcher.Invoke(() => ShowErrorRequested?.Invoke(this, LocalizationHelper.Get("S.ImportVideo.Error") + Environment.NewLine + e.Message + Environment.NewLine + e.HelpLink));
        }
    }

    private void ImportAndSeek()
    {
        if (_cancelled)
            return;

        lock (_lock)
        {

View on GitHub (pinned to a4d0a67c21)

Solutions

Read the exception's HelpLink which contains the FFmpeg command and stderr output — this pinpoints the exact FFmpeg error.
Verify the FFmpeg binary version supports the input codec (run 'ffmpeg -codecs').
Check the input video file is not corrupted (play it in a media player).
Ensure the output/temp directory has write permissions and sufficient disk space.
Update FFmpeg to a recent build with all common codecs enabled.

Example fix

// before
if (!string.IsNullOrWhiteSpace(error))
    throw new Exception("Error while capturing frames with FFmpeg.") { HelpLink = $"Command:\n\r{info.Arguments}\n\rResult:\n\r{error}" };

// after: include error directly in message for easier debugging, check exit code
if (_process.ExitCode != 0 || !string.IsNullOrWhiteSpace(error))
    throw new Exception($"Error while capturing frames with FFmpeg (exit {_process.ExitCode}): {error}")
    { HelpLink = $"Command:\n\r{info.Arguments}" };

Defensive patterns

Strategy: try-catch

Validate before calling

// Validate input file before starting FFmpeg
if (!File.Exists(inputPath))
    throw new FileNotFoundException("Input video not found", inputPath);
var info = new FileInfo(inputPath);
if (info.Length == 0)
    throw new InvalidDataException("Input video file is empty.");
if (!File.Exists(ffmpegPath))
    throw new FileNotFoundException("FFmpeg binary not found", ffmpegPath);

Try / catch

// The existing catch block at line 770 already handles this:
// it logs, sets IsImporting=false, and shows a user error dialog.
// Ensure e.HelpLink (containing FFmpeg stderr) is shown to the user.

Prevention

Validate the input video file exists and is non-empty before launching FFmpeg.
Verify the FFmpeg binary path and version before use.
Check that the output/temp directory has write permission and free disk space.
Parse FFmpeg's exit code separately from stderr — exit code 0 with stderr output is normal for FFmpeg.

When it happens

Trigger: FFmpeg process runs (info.Arguments) and exits, but writes error messages to stderr. Common FFmpeg errors: unsupported codec, corrupt input file, invalid arguments, missing encoder, permission denied on output path, or the input video file is unreadable.

Common situations: User selects a video with a codec FFmpeg doesn't support (rare but possible with custom builds). FFmpeg binary is not found or is an older version lacking the needed decoder. Output folder is read-only. Input video file is corrupted or truncated. FFmpeg arguments (e.g., filter, fps) are misconfigured.

Related errors

AI-assisted analysis of NickeManarin/ScreenToGif@a4d0a67c21 (2026-08-13). Data as JSON: /api/errors/e2a69bab63a3a497. Report an issue: GitHub.