NickeManarin/ScreenToGif · error · Exception

Error while encoding the {preset.Type} with FFmpeg.

Error message

Error while encoding the {preset.Type} with FFmpeg.

What it means

EncodeWithFfmpeg completes the ffmpeg process run (optionally a second pass) and then inspects new FileInfo(preset.FullPath). If the output file does not exist or has Length == 0, it throws Exception with a HelpLink carrying the firstPass+secondPass commands and the captured ffmpeg log. The exception means ffmpeg ran but produced no usable output.

Source

Thrown at ScreenToGif/Util/EncodingManager.cs:1862

        }

        var fileInfo = new FileInfo(preset.FullPath);

        //Execute the second pass, cleaning up the logs.
        if (!string.IsNullOrWhiteSpace(secondPass))
        {
            //I could try using as a single command.
            //ffmpeg -y -hwaccel auto {I} -c:v h264_nvenc -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -pass 1 -f avi NUL
            //&&
            //ffmpeg -y -hwaccel auto {I} -c:v h264_nvenc -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -pass 2 -f avi {O}

            log += Environment.NewLine + SecondPassFfmpeg(secondPass, id, tokenSource, LocalizationHelper.Get("S.Encoder.Processing.Second"));

            EraseSecondPassLogs(preset.FullPath);
        }

        if (!fileInfo.Exists || fileInfo.Length == 0)
            throw new Exception($"Error while encoding the {preset.Type} with FFmpeg.") { HelpLink = $"Command:\n\r{firstPass + Environment.NewLine + secondPass}\n\rResult:\n\r{log}" };
    }

    private static string SecondPassFfmpeg(string command, int id, CancellationTokenSource tokenSource, string processing)
    {
        var log = "";

        var process = new ProcessStartInfo(UserSettings.All.FfmpegLocation)
        {
            Arguments = command,
            CreateNoWindow = true,
            ErrorDialog = false,
            UseShellExecute = false,
            RedirectStandardError = true
        };

        using (var pro = Process.Start(process))
        {
            var indeterminate = true;

View on GitHub (pinned to a4d0a67c21)

Solutions

1. Read the HelpLink — it contains the exact ffmpeg commands and the full log identifying the failure line.
2. Update ffmpeg to a recent static build that includes the needed encoders (libx264, libvpx-vp9, etc.).
3. If using hardware acceleration (nvenc/qsv), verify the GPU supports it or fall back to software encoders.
4. Verify preset.FullPath's folder is writable and excluded from AV scanning.

Example fix

// before
if (!fileInfo.Exists || fileInfo.Length == 0)
    throw new Exception($"Error while encoding the {preset.Type} with FFmpeg.") { HelpLink = $"Command:\n\r{firstPass + Environment.NewLine + secondPass}\n\rResult:\n\r{log}" };

// after
if (!fileInfo.Exists || fileInfo.Length == 0)
    throw new Exception($"Error while encoding the {preset.Type} with FFmpeg. Output missing or empty. See HelpLink for command and log.") { HelpLink = $"Command:\n\r{firstPass + Environment.NewLine + secondPass}\n\rResult:\n\r{log}" };

// Pre-flight: confirm the encoder exists in this ffmpeg build
var encoders = await PathHelper.GetFfmpegEncoders(); // -encoders output parsed
if (!encoders.Contains(requiredEncoder)) /* warn user */

// n/a

try { await EncodeWithFfmpeg(...); }
catch (Exception ex)
{
    var log = ex.HelpLink; // contains command + ffmpeg log
    LogWriter.Log(ex, $"ffmpeg encode failed.\n{log}");
    throw;
}

When it happens

Trigger: ffmpeg exited but preset.FullPath is missing or zero bytes. Typical causes: ffmpeg returned non-zero (bad codec, missing encoder build, invalid filter), the two-pass first pass failed silently, an invalid scale/pix_fmt argument, frames missing on disk, or the output path was unwritable.

Common situations: ffmpeg build without the required encoder (e.g. no libx264 / libvpx / h264_nvenc); older ffmpeg version (HasOlderFfmpegVersion) using deprecated flags; corrupted/empty source frames; AV quarantining output; unsupported hardware acceleration flag on a GPU that lacks it.

Related errors

• Error while encoding the gif with Gifski. Empty output file.
• FFmpeg not present.
• Gifski not present.
• Error while capturing frames with FFmpeg.
• Missing upload preset called {preset.UploadService}

AI-assisted analysis of NickeManarin/ScreenToGif@a4d0a67c21 (2026-08-13). Data as JSON: /api/errors/cbc31121fd1086ff. Report an issue: GitHub.