Engines
Downloaders are the core of the application. They are responsible for downloading the video stream from the source. The application supports three downloaders: Mesio, FFMPEG, and Streamlink. Each downloader has its own features and limitations.
TIP
For Mesio users, it is highly recommended to enable both FLV Consistency Fix and HLS Consistency Fix. These features ensure the recorded files remain playable and consistent even when the source stream encounters issues like timestamp jumps or network interruptions.
The FFMPEG downloader is the default downloader and is the most stable and reliable. It is written in C and is capable of downloading FLV and HLS streams. It provides excellent compatibility for various streaming scenarios, including support for non-standard HEVC in FLV/RTMP containers. It is the most efficient downloader in terms of CPU and memory usage. However, it does not support multithreading for HLS downloads.
NOTE
The FFMPEG version provided in our Docker images is a specialized build from yt-dlp/FFmpeg-Builds. This build is optimized for streaming and includes (or has upstreamed) critical patches for smooth integration with yt-dlp, such as fixing AAC HLS truncation, supporting long paths on Windows, and decoding non-standard HEVC in FLV containers.
1. Engines Feature List
| Feature | Mesio | FFMPEG | STREAMLINK |
|---|---|---|---|
| FLV Download | ✅ | ✅ | ❌ |
| HLS Download | ✅ (Multithreaded) | ✅ | ✅ (Multithreaded) |
| Recording Duration Stats | ✅ (Raw data mode not supported) | ✅ | ✅ |
| Download Bitrate Stats | ✅ | ✅ (-f segmentation not supported) | ✅ (-f segmentation not supported) |
| Size Segmentation | ✅ (Raw data mode not supported) | ✅ (-f segmentation not supported) | ✅ |
| Duration Segmentation | ✅ (Raw data mode not supported) | ✅ | ✅ |
| Download Format | FLV, M3U8, TS, M4S | Supports other formats | Supports other formats |
| FLV Consistency Fix | ✅ (Recommended) | ❌ | ❌ |
| HLS Consistency Fix | ✅ (Recommended) | ❌ | ❌ |
| CPU Usage | Lowest | Low | Low |
| Memory Usage | Lowest | Low | Medium |
2. FLV Consistency Fix Feature List
| Feature | Engine Action |
|---|---|
| Timestamp Jumps | Fix using delta |
| Video Header Changes (Resolution, Other Parameters) | Split file |
| Audio Header Changes | Split file |
| AMF Metadata Injection (lastheadertimestamp, keyframes...) | Inject |
| Duplicate TAG (experimental) | Ignore |
3. Raw Data Mode
Raw Data Mode is a high-performance download mode supported by the Mesio engine. In this mode, the engine writes the stream data directly to the disk as it's received from the network, without parsing or processing the internal media packets (headers, frames, metadata).
Key Characteristics:
- Maximum Performance: Since there is no packet parsing or re-muxing, CPU and memory usage are at their absolute minimum.
- Zero Overhead: Ideal for high-bandwidth streams or resource-constrained environments (like low-end NAS or VPS). Only recommended if the network is stable and the CDN/stream source has no data fluctuations (e.g., media headers changing).
Limitations:
Because the headers and packet structures are not inspected, some advanced features are unavailable when Raw Data Mode is enabled:
- Statistics: Recording duration and bitrate stats cannot be calculated in real-time.
- Segmentation: The engine cannot detect frame boundaries or duration, so it cannot perform precise segmentation by size or duration.
- Repair: Features like FLV Consistency Fix or HLS Consistency Fix cannot be applied as they require packet-level manipulation.
4. HLS Consistency Fix (Mesio Exclusive)
When using the Mesio engine for HLS streams, the HLS Consistency Fix feature can automatically detect and resolve common HLS delivery issues, such as timestamp discontinuities or missing segments, before the data is written to the final file. This ensures a smoother playback experience for the recorded content.