Selecting the proper imaging technology up front will be one of your most important decisions you will face designing and implementing your network video project. When considering compression options for network video solutions, the following video related issues should be reviewed and carefully considered.
- Minimum Resolution
- Image Quality
- Minimum and Maximum Frame Rates (FPS)
- Number of Cameras (Scalability)
- Storage Requirements
- Available Bandwidth
- Overall Latency (time difference between live and displayed video)
- Budget
The compression logic used in both MJPEG and MPEG4 are beyond the scope of this white paper. Suffice it to say that MJPEG and MPEG4 compression algorithms are the most common forms of video compression currently used in the network video industry.
MJPEG/JPEG Analysis
Pros
- Well Suited For Mega-Pixel Cameras
- Better Image Quality (clear individual images)
- Resiliency (fast image stream recovery in the event of packet loss)
- Interoperability (industry standard compression/decompression available on all PCs)
- Decompression on the PC is better (more video streams on PC)
- Large Number of Supported Cameras
- Lower Latency (better live viewing and more responsive PTZ control)
- Graceful degradation (reduced bandwidth does not reduce image quality)
- Constant image quality (quality remains constant regardless of image complexity)
- Can Perform Live Motion Detection and Image Analysis (at the PC)
- Low complexity (for images searches and manipulation)
- Can display and record up to 30 FPS
Cons
- High bandwidth usage (at frame rates above 10 FPS)
- High storage requirements (at frame rates above 10 FPS)
- No support for synchronized sound
- Higher compression Rates (above 10 FPS)
- Lower storage requirements (at 10 FPS or higher)
- Can Maintain Constant bit rate (CBR)
- Good Streaming Protocol (designed for real-time viewing)
- Can Sync Audio and Video (for live and recorded streams)
- Can display and record up to 30 FPS
Cons
- Decompression on the PC is quite high (fewer video streams)
- Low robustness (can lose video if bandwidth drops)
- Higher latency (delayed live viewing and sluggish PTZ control)
- Protocol Issues (not designed for recording and analysis)
- Few Number of Supported Cameras
- Less Resilient (packet loss causes lost video)
- Can Not Perform Live Motion Detection and Image Analysis (at the PC)
- CBR Mode Issues (image quality suffers with network congestion or movement in scenes)
- Licensing restrictions (may need to pay for viewers)
- Not Suited For Mega-Pixel Cameras
If you require synchronized audio and video then MPEG4 is the clear choice. For most security surveillance and remote monitoring applications the MJPEG compression technology is the best choice.