DVD-Video primarily utilizes MPEG-2 Part 2 (also known as H.262) for video compression, with MPEG-1 Part 2 as an alternative option for specific scenarios. These formats are fundamental to how digital video is stored and played back on a DVD disc.
The Primary Video Codec: MPEG-2 (H.262)
For recording digital video, the dominant codec used in the DVD-Video standard is MPEG-2 Part 2, which is officially designated as H.262 by the ITU-T. This codec was chosen for its efficiency and ability to deliver high-quality video suitable for television screens of its era.
- Compression: MPEG-2 employs a sophisticated inter-frame and intra-frame compression scheme, reducing file sizes significantly while maintaining visual fidelity.
- Bitrate: DVD-Video typically uses MPEG-2 compression at a variable bitrate, peaking at 9.8 Mbit/s (9,800 kbit/s). This high bitrate allows for detailed imagery and smooth motion, crucial for a good viewing experience.
- Resolution: MPEG-2 on DVDs supports standard definition resolutions, most commonly 720x480 (NTSC) or 720x576 (PAL).
- Purpose: It's the standard for virtually all commercially released DVD movies and TV shows, offering a balance between video quality and disc storage capacity.
The Alternative Video Codec: MPEG-1
While less common for primary feature content, MPEG-1 Part 2 is also supported by the DVD-Video specification as an alternative video compression format. MPEG-1 is an older standard, primarily known for its use in Video CD (VCD) and early digital video applications.
- Compression: MPEG-1 uses a simpler compression method compared to MPEG-2.
- Bitrate: When used on DVD, MPEG-1 Part 2 compression is limited to a lower maximum bitrate of 1.856 Mbit/s (1,856 kbit/s).
- Resolution: Typically supports lower resolutions, often 352x240 (NTSC) or 352x288 (PAL), which is roughly half the resolution of standard DVD-Video.
- Purpose: It might be used for supplementary content, older footage, or in regions where lower quality and smaller file sizes are acceptable or necessary. Its inclusion also provided a degree of backward compatibility with existing MPEG-1 decoders.
Key Characteristics of DVD Video Codecs
Understanding the video codecs used on DVDs highlights their capabilities and limitations. Here's a quick overview of the primary video compression formats:
| Codec Name | Official Standard | Maximum Bitrate | Common Resolutions | Primary Use Case |
|---|---|---|---|---|
| MPEG-2 Part 2 | H.262 (ISO/IEC 13818-2) | 9.8 Mbit/s (9,800 kbit/s) | 720x480, 720x576 | Standard for DVD-Video main features |
| MPEG-1 Part 2 | ISO/IEC 11172-2 | 1.856 Mbit/s (1,856 kbit/s) | 352x240, 352x288 | Alternative, supplementary content, older media |
These codecs, along with associated audio codecs like Dolby Digital (AC-3) and DTS, define the DVD-Video standard, enabling a rich multimedia experience that was revolutionary at its time. For more in-depth information on these standards, you can refer to resources like the MPEG-2 Wikipedia page or the DVD-Video Wikipedia page.
