Output

Defines the output file for an FFmpeg session. This node specifies where processed media will be saved and what encoding parameters to apply.

Common Properties

• Name - The custom name of the node.
• Color - The custom color of the node.
• Delay Before (sec) - Waits in seconds before executing the node.
• Delay After (sec) - Waits in seconds after executing node.
• Continue On Error - Automation will continue regardless of any error. The default value is false.

info

If the ContinueOnError property is true, no error is caught when the project is executed, even if a Catch node is used.

Inputs

• stream_id - Stream ID from an Input or Filter node. This is the primary stream that will be written to the output file.
• Output File Path - Path where the output file will be saved. The file extension determines the output format (e.g., .mp4, .avi, .webm, .mp3).
• Additional Stream IDs - Optional array of additional stream IDs to include in the output. Useful for:
  • Combining video and audio from separate sources
  • Including multiple audio tracks
  • Merging subtitle streams

Options

• Output File Options - Array of FFmpeg output options. These control the encoding and output parameters. Examples:

  • ["c:v=libx264"] - Use H.264 video codec
  • ["b:v=2M"] - Set video bitrate to 2 Mbps
  • ["c:a=aac"] - Use AAC audio codec
  • ["preset=fast"] - Use fast encoding preset
  • ["crf=23"] - Set quality level (lower = better quality)

• Custom Output File Options - Individual output options added as separate fields. Each option should follow the format:

  • key=value for options with values (e.g., c:v=libx264)
  • key only for flags

Output

• stream_id - Output stream identifier. This must be passed to the Run node to execute the FFmpeg command.

How It Works

The Output node defines the final destination and encoding parameters for your media processing pipeline. When executed, the node:

1. Validates the input stream ID and output file path
2. Retrieves the input stream(s) from the session
3. Parses output options
4. Creates an FFmpeg output stream with the specified settings
5. Returns an output stream ID for use with the Run node

Output Options Reference

Video Encoding Options

Option	Description	Example
c:v or codec:v	Video codec	c:v=libx264, c:v=libx265, c:v=vp9
b:v	Video bitrate	b:v=2M (2 Mbps), b:v=500k (500 kbps)
crf	Constant Rate Factor (quality)	crf=23 (default), crf=18 (high quality)
preset	Encoding speed preset	preset=fast, preset=slow (better quality)
r	Frame rate	r=30 (30 fps), r=60 (60 fps)
s	Resolution	s=1920x1080, s=1280x720
pix_fmt	Pixel format	pix_fmt=yuv420p

Audio Encoding Options

Option	Description	Example
c:a or codec:a	Audio codec	c:a=aac, c:a=libmp3lame, c:a=opus
b:a	Audio bitrate	b:a=192k (192 kbps), b:a=128k (128 kbps)
ar	Audio sample rate	ar=48000 (48 kHz), ar=44100 (44.1 kHz)
ac	Audio channels	ac=2 (stereo), ac=1 (mono)

General Output Options

Option	Description	Example
f	Force format	f=mp4, f=webm
t	Duration	t=60 (60 seconds)
ss	Start time	ss=00:00:10 (start at 10 seconds)
map	Stream mapping	map=0:v:0, map=1:a:0
movflags	MP4 flags	movflags=+faststart (web optimization)

Example Usage

Basic MP4 Output

Save processed video as MP4:

// Output node settings:
{
  "Output File Path": "/path/to/output.mp4"
}

High-Quality H.264 Output

Create high-quality video with H.264 codec:

// Output File Options:
["c:v=libx264", "crf=18", "preset=slow", "c:a=aac", "b:a=192k"]

Web-Optimized Video

Create a video optimized for web streaming:

// Output File Options:
["c:v=libx264", "preset=fast", "movflags=+faststart", "c:a=aac", "b:a=128k"]

Compressed Video for Storage

Reduce file size with higher compression:

// Output File Options:
["c:v=libx265", "crf=28", "preset=slow", "c:a=aac", "b:a=96k"]

Audio-Only Output

Extract audio to MP3:

{
  "Output File Path": "/path/to/audio.mp3",
  "Output File Options": ["c:a=libmp3lame", "b:a=320k"]
}

Multiple Stream Output

Combine video from one source with audio from another:

// Assuming:
// video_stream_id from Input node (video file)
// audio_stream_id from Input node (audio file)

{
  "stream_id": video_stream_id,
  "Additional Stream IDs": [audio_stream_id],
  "Output File Path": "/path/to/combined.mp4",
  "Output File Options": ["c:v=copy", "c:a=aac", "b:a=192k"]
}

Copy Streams (No Re-encoding)

Copy streams without re-encoding for fast processing:

// Output File Options:
["c=copy"]
// or separately:
["c:v=copy", "c:a=copy"]

Practical RPA Scenarios

Scenario 1: Convert Screen Recording to Web Format

Convert a screen recording to web-optimized MP4:

Create → Input (recording.avi) → Output (recording.mp4) → Run

Output settings:
{
  "Output File Options": [
    "c:v=libx264",
    "preset=fast",
    "crf=23",
    "movflags=+faststart",
    "c:a=aac",
    "b:a=128k"
  ]
}

Scenario 2: Create Video Thumbnail

Extract a single frame as an image:

// Output File Path: "/path/to/thumbnail.jpg"
// Output File Options:
["vframes=1", "ss=00:00:05"]
// Extracts frame at 5 seconds

Scenario 3: Reduce Video File Size

Compress video for email or upload:

// Output File Options:
["c:v=libx264", "crf=28", "preset=fast", "s=1280x720", "c:a=aac", "b:a=96k"]
// Reduces resolution to 720p with higher compression

Scenario 4: Extract Audio Track

Save only the audio from a video:

// Output File Path: "/path/to/audio.mp3"
// Output File Options:
["vn", "c:a=libmp3lame", "b:a=192k"]
// vn = no video

Scenario 5: Replace Audio in Video

Combine video from one file with audio from another:

Create →
  Input (video.mp4) → video_stream
  Input (audio.mp3) → audio_stream
→ Output (combined.mp4, streams=[video_stream, audio_stream]) → Run

Output File Options:
["c:v=copy", "c:a=aac", "b:a=192k", "map=0:v", "map=1:a"]

Format-Specific Examples

MP4 (H.264/AAC)

["c:v=libx264", "crf=23", "preset=medium", "c:a=aac", "b:a=128k", "movflags=+faststart"]

WebM (VP9/Opus)

["c:v=libvpx-vp9", "crf=30", "b:v=0", "c:a=libopus", "b:a=128k"]

High-Quality Archive (H.265/AAC)

["c:v=libx265", "crf=20", "preset=slow", "c:a=aac", "b:a=256k"]

GIF Animation

["vf=fps=10,scale=320:-1:flags=lanczos", "f=gif"]

Error Handling

The node will return errors in the following cases:

• "Stream Id cannot be empty" - No stream_id provided
• "Invalid stream id" - The provided stream_id doesn't exist in the session
• Invalid option format - Output options are not properly formatted

Usage Notes

• The output file format is determined by the file extension
• Some codecs may not be available depending on your FFmpeg build
• Using c=copy or c:v=copy copies streams without re-encoding (fastest)
• The CRF (Constant Rate Factor) scale is 0-51, where lower values mean better quality
• For web videos, use movflags=+faststart to enable progressive playback
• Multiple audio tracks can be added using Additional Stream IDs
• The actual file is not created until the Run node executes

Performance Tips

1. Use Copy When Possible: If no conversion is needed, use c=copy to avoid re-encoding
2. Choose Appropriate Presets: Use preset=fast for speed or preset=slow for better quality
3. Balance Quality and Size: CRF 23 is a good balance; adjust based on needs
4. Limit Resolution: Downscale video if high resolution isn't needed
5. Optimize for Target Platform: Use format-specific optimizations (e.g., movflags=+faststart for MP4)

Common Errors and Solutions

Error: "Output file already exists"

Cause: The output file exists and overwrite is not enabled. Solution: Enable the Overwrite option in the Run node or delete the existing file first.

Error: "Unknown encoder"

Cause: The specified codec is not available in your FFmpeg build. Solution: Use a different codec or verify FFmpeg installation supports the codec.

Error: "Invalid argument"

Cause: Malformed option or incompatible option combination. Solution: Check option syntax and ensure options are compatible with the output format.

Error: "Option not found"

Cause: Using an option that doesn't exist or is misspelled. Solution: Verify option names against FFmpeg documentation.

Best Practices

1. Test Output Settings: Start with default settings, then optimize as needed
2. Use Descriptive Paths: Include format and quality in output filenames (e.g., video_720p_compressed.mp4)
3. Enable Fast Start: Always use movflags=+faststart for web video
4. Preserve Quality When Needed: Use c=copy or low CRF values for archival purposes
5. Consider File Size: Balance quality and file size based on use case
6. Validate Output: Use Probe node after processing to verify output properties

Related Nodes

• Input - Provides the source streams for this node
• Filter - Can process streams before output
• Run - Executes the FFmpeg command to create the output file
• Create - Initializes the session containing all streams