This information compares the capabilities of different video recorders. http://www.digiop.com/products/hybrid-dvrs

1. DIGIOP D-Series Video Recorders
All DIGIOP NVR s and FlexVR™ recorders feature DIGIOP's
simple, cost-effective licensing model, Open IP License. All video
channels come pre-licensed and fully-enabled, allowing users to
add cameras as their system needs require (up to 32 channels
per system), without having to purchase additional licenses.
Licenses never expire and there are no recurring fees,
minimizing total cost of ownership over the life of the product.
What's the Difference?
DM-Series
DIGIOP’s DM Series MPEG-4 Hybrid FlexVR line extends
beyond traditional hybrid DVRs to provide the flexibility to
choose the number of analog and IP cameras you want to
connect to the system – within the allotted total number of
channels supported by the DVR – without pre-determined
channel limitations.
DIGIOP DM-series hybrid DVR features MPEG-4 video compression, which is designed to support
low-bandwidth applications while still offering a great compression rate and optimizing storage
availability. Our MPEG-4 configuration allows the user to set compression card settings once, and
apply them to all video channels, making setup easy and user-friendly.
DIGIOP DM-Series is available in a Core and Performance series option to allow the customer to
choose how much live video viewing will be performed on the Recorder.
DM Series spec sheet: English (PDF)

2. DH-Series
DIGIOP’s DH Series Real-time Hybrid FlexVR line extends
beyond traditional hybrid DVRs to provide the flexibility to
choose the number of analog and IP cameras you want to
connect to the system – within the allotted total number of
channels supported by the DVR – without pre-determined
channel limitations.
DIGIOP DH-series hybrid DVR features H.264 video compression, which allows for higher
compression rates, coupled with higher quality video, meaning DIGIOP DH-series Recorders can
store more video than a system with a lesser quality compression card. Our H.264 configuration
allows the user to configure settings within each channel of the compression card for maximum
flexibility of each analog channel!
DIGIOP DH-Series is available in a Core and Performance series option to allow the customer to
choose how much live video viewing will be performed on the Recorder.
DH Series spec sheet: English (PDF)
DI-Series
DIGIOP’s DI Series 32-Channel NVRs come equipped with a 32-camera Open IP License that
enables you to add as many cameras as you need – when and where you need them.
The DI-Series relies on the IP camera’s frame rate and resolution capabilities to determine its
recording settings. Each video stream is configurable on a per-channel basis for maximum flexibility
of each IP channel.

3. DIGIOP DI-Series is available in a Core and Performance series option to allow the customer to
choose how much live video viewing will be performed on the Recorder.
DI-Series spec sheet: English (PDF)
http://www.digiop.com/products/hybrid-dvrs