Clip Service

The ClipService handles creating clips from recorded sessions and replay buffers. It uses FFmpeg to extract segments, apply encoding settings, and concatenate multiple selections into a single output file.

Overview

Implemented in Backend/Media/ClipService.cs, the service provides:

Extract multiple segments from different source videos
Concatenate segments into a single clip
Re-encode with configurable quality settings
Hardware and software encoding support
Progress tracking and cancellation
Automatic metadata generation

Core Methods

CreateClips

Creates a clip from one or more video selections.

public static async Task CreateClips(List<Selection> selections)

selections

List<Selection>

List of video segments to include in the clip. Each selection contains:

Game: Game name
FileName: Source video filename
FilePath: Full path to source video (optional, auto-resolved if missing)
Type: Content type (Session, Buffer, or Clip)
StartTime: Start time in seconds
EndTime: End time in seconds
Title: Optional clip title
IgdbId: Optional IGDB game ID

Process Flow:

Validates selections and calculates total duration
Extracts each segment to a temporary file
Concatenates temporary files (if multiple selections)
Generates metadata, thumbnail, and waveform
Adds clip to content library
Cleans up temporary files

Progress Events: Sends ClipProgress messages to the frontend with:

id: Unique clip operation ID
progress: Progress percentage (0-100, or -1 for error)
selections: The original selections list
error: Error message (only when progress = -1)

var selections = new List<Selection>
{
    new Selection
    {
        Game = "Valorant",
        FileName = "2026-03-03_14-30-00",
        Type = "Session",
        StartTime = 45.5,
        EndTime = 78.2,
        Title = "Ace Round"
    }
};

await ClipService.CreateClips(selections);

CancelClip

Cancels an in-progress clip operation.

public static async void CancelClip(int clipId)

clipId

int

The unique ID of the clip operation to cancel (provided in ClipProgress messages)

Behavior:

Kills all active FFmpeg processes associated with the clip ID
Removes processes from tracking
Sends completion message to frontend
Cleanup of temporary files is handled by the original CreateClips task

Example Usage

// From frontend message handler
int clipId = 123456789;
ClipService.CancelClip(clipId);

Cancellation is immediate and forces FFmpeg process termination. Partial output files are automatically cleaned up.

Encoding Configuration

The service uses settings from Settings.Instance to configure encoding:

Encoder Selection

ClipEncoder

string

"gpu": Use hardware acceleration
"cpu": Use software encoding

Codec Selection

ClipCodec

string

"h264": H.264/AVC
"h265": H.265/HEVC
"av1": AV1

Hardware Encoder Settings

NVIDIA (NVENC):

ClipQualityGpu

int

CQ level for NVENC (lower = higher quality, typical range: 15-35)

ClipPreset

string

NVENC preset: p1 (fastest) to p7 (slowest), or Quality, Performance

FFmpeg arguments: -cq {quality} -preset {preset} AMD (AMF):

ClipQualityGpu

int

QP level for AMF (lower = higher quality, typical range: 15-35)

ClipPreset

string

AMF usage mode: quality, transcoding, lowlatency, ultralowlatency

FFmpeg arguments: -rc cqp -qp_i {quality} -qp_p {quality} -usage {preset} Intel (QuickSync):

ClipQualityGpu

int

Global quality for QSV ICQ mode (lower = higher quality, typical range: 15-35)

ClipPreset

string

QSV preset: veryfast, faster, fast, medium, slow, slower, veryslow

FFmpeg arguments: -global_quality {quality} -preset {preset}

Software Encoder Settings

ClipQualityCpu

int

CRF value for libx264/libx265 (lower = higher quality, typical range: 18-28)

ClipPreset

string

x264/x265 preset: ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow

FFmpeg arguments: -crf {quality} -preset {preset}

Additional Settings

ClipFps

int

Target frame rate (0 = keep source frame rate)

ClipAudioQuality

string

AAC audio bitrate (e.g., "128k", "192k", "256k", "320k")

Codec Matrix

The service automatically selects the appropriate codec based on encoder and codec settings:

GPU Vendor	ClipCodec	FFmpeg Encoder
NVIDIA	h264	`h264_nvenc`
NVIDIA	h265	`hevc_nvenc`
NVIDIA	av1	`av1_nvenc`
AMD	h264	`h264_amf`
AMD	h265	`hevc_amf`
AMD	av1	`av1_amf`
Intel	h264	`h264_qsv`
Intel	h265	`hevc_qsv`
Intel	av1	`av1_qsv`
CPU	h264	`libx264`
CPU	h265	`libx265`
CPU	av1	Not supported (falls back to libx264)

If GPU vendor detection fails, the service automatically falls back to CPU encoding with a warning log message.

FFmpeg Command Examples

Single Clip Extraction

ffmpeg -y -ss 45.5 -t 32.7 \
  -i "input.mp4" \
  -c:v h264_nvenc -preset p4 -cq 20 -r 60 \
  -c:a aac -b:a 192k \
  -movflags +faststart \
  "output.mp4"

Multi-Clip Concatenation

ffmpeg -y -f concat -safe 0 \
  -i "concat_list.txt" \
  -c copy \
  -movflags +faststart \
  "output.mp4"

Where concat_list.txt contains:

file 'C:\\Temp\\clip123.mp4'
file 'C:\\Temp\\clip456.mp4'

File Organization

Clips are saved to:

ContentFolder/clips/{GameName}/{Timestamp}.mp4

Example:

C:/Users/User/Videos/Segra/clips/Valorant/2026-03-03_14-45-30.mp4

Each clip includes:

Video file: {timestamp}.mp4
Metadata: {timestamp}.json (game, title, timestamps, IGDB ID)
Thumbnail: {timestamp}.jpg
Waveform: {timestamp}_waveform.png

Progress Tracking

The service tracks progress at multiple stages:

Progress %	Stage
0-95%	Extracting and encoding segments
96%	Concatenating segments
97%	Verifying output file
98%	Generating metadata
99%	Creating thumbnail and waveform
100%	Complete - loading into library
-1	Error occurred

Progress is weighted by clip duration:

double currentProgress = (processedDuration + (progress * clipDuration)) / totalDuration * 95;

Error Handling

The service includes comprehensive error handling:

Validation Errors

Empty selections list
Zero or negative total duration
FFmpeg not found
Missing source files

Extraction Errors

Failed to create temp clip file
FFmpeg process errors
Cancellation during extraction

Concatenation Errors

Failed to create output file
File not ready for metadata generation

Cleanup

All temporary files are cleaned up in the finally block:

Individual clip segments
Concat list file
Partial output files (on error)

Errors are logged with full stack traces and reported to the frontend via ClipProgress messages with progress: -1 and an error description.

Thread Safety

The service uses a ProcessLock object to ensure thread-safe access to the active FFmpeg process dictionary:

lock (ProcessLock)
{
    ActiveFFmpegProcesses[clipId] = process;
}

This prevents race conditions when:

Adding processes during extraction
Removing processes after completion
Cancelling clips from frontend

Integration Points

FFmpegService: Executes FFmpeg with progress callbacks
ContentService: Generates thumbnails, metadata, and waveforms
SettingsService: Loads clips into content library
StorageService: Sanitizes game names for folder organization
MessageService: Sends progress updates to frontend

Overview

Core Services

​Overview

​Core Methods

​CreateClips

​CancelClip

​Encoding Configuration

​Encoder Selection

​Codec Selection

​Hardware Encoder Settings

​Software Encoder Settings

​Additional Settings

​Codec Matrix

​FFmpeg Command Examples

​Single Clip Extraction

​Multi-Clip Concatenation

​File Organization

​Progress Tracking

​Error Handling

​Validation Errors

​Extraction Errors

​Concatenation Errors

​Cleanup

​Thread Safety

​Integration Points

Overview

Core Methods

CreateClips

CancelClip

Encoding Configuration

Encoder Selection

Codec Selection

Hardware Encoder Settings

Software Encoder Settings

Additional Settings

Codec Matrix

FFmpeg Command Examples

Single Clip Extraction

Multi-Clip Concatenation

File Organization

Progress Tracking

Error Handling

Validation Errors

Extraction Errors

Concatenation Errors

Cleanup

Thread Safety

Integration Points