Blu-ray and DVD both are optical disk storage formats and also appeared similar to each other. But both the storage formats are much different from each other. Blu-ray is the modern disk storage format and provides several advantages over DVDs. The main difference between Blu-ray and DVD is storage capacity and streaming quality. Compared to the DVDs, Blu-ray can store a huge amount of data, and also, the video quality is much better than DVD. In this topic, we will understand what Blu-ray and DVDs are and how these two are differentiated from each other.

What is DVD?

DVD stands for "Digital Versatile Disk" or "Digital Video Disc". It is a digital optical disc storage format, which is used to store any kind of digital data and is especially used to store photographs, music, and videos. Some DVDs are mainly used to store the videos that can be watched using DVD players, while others may have software programs or computer files.

The first DVD format was invented and developed in the year 1995 and was released in the year 1996. It can store a huge amount of data compared to compact discs or CDs within the same dimensions. It also provides better picture quality compared to CD and VHS, with larger data pits.

Advantages

  • It can provide standard definition video quality.
  • It is cost-effective.
  • Compatible with old and modern DVD players and with BDPs.
  • It is durable

Disadvantages

  • Storage capacity is less compared to modern or Blu-ray discs.
  • It cannot provide high-definition quality images.

What is Blu-ray?

Blu-ray is a digital disc storage format similar to CD and DVD, which is designed to record and play a huge amount of data with high-definition quality. It can store several hours of videos with high-quality. It is named "Blu-ray" because blue laser is used to read the disc, which enables to store the information at greater density compared to red-laser used in DVD. It is because the blue-violet has a shorter wavelength compared to the red laser, which allows the user to store more information within a smaller area.

Blu-ray is the advanced version of DVDs, and it was developed collaboratively by Hitachi, LG, Matsushita (Panasonic), Pioneer, Philips, Samsung, Sharp, Sony, and Thomson in the year 2006.

The size of the Blu-ray disc is 120 millimeters in diameter with 1.2 millimeters thickness, which is the same as the size of a CD and DVD.

The storage capacity of Blu-ray is 25 GB per single layer and 50 GB for dual-layer.

A Blu-ray disc cannot be played on current CD and DVD players, as these players lack the blue-violet laser, which is required to read the Blu-ray disc. However, the CD and DVD can be played by the Blu-ray disc players (BDPs).

Advantages

  • It can store a large amount of data within one disc.
  • It provides high-quality videos.
  • It provides backward compatibility.

Disadvantage

  • It is not cost-effective as DVDs
  • A Blu-ray disc cannot be played using DVD players.

How to find the best Blu-ray disc?

The common question among the Blu-ray buyers is that how to choose and identify the best Blu-ray disc. But unfortunately, we cannot identify it by checking the box-cover.

Generally, movies and TV shows released from 2006 onwards will look good on Blu-ray, as the original content is adapted to be transferred to high-definition Blu-ray discs. But the old movies may not look as good, as they are provided with the re-master treatment. Hence, it is recommended to check if Blu-ray has been remastered (from the original source).

Feature comparison between Blu-rays and DVD

Now let's compare the Blu-ray and DVD based on different features:

  • Storage Capacity
    As already discussed in the introduction section, Blu-ray disc formats are capable of storing a huge amount of data compared to DVD. In general, a standard DVD can store 4.7 GB of data, which means a movie of 2 hours. But if a movie is for more than 2 hours, then we need two DVDs or double-layer DVDs that can store up to 9GB of data. In contrast, a Blu-ray disc can store 25 GB of data in a single-layer and up to 50 GB of data in a double-layer disc.
  • Image Resolution
    Image resolution defines the quality of the picture, and it means how the picture looks when we are playing the disc. For DVDs, the picture quality is of standard definition or 480SD, but we cannot get the high-definition video picture quality using DVDs. At the same time, Blu-ray discs are designed to provide high-definition picture quality. It provides us the best possible picture with 1080HD capability.
  • Laser technology used
    Both Blu-rays and DVDs disc are based on optical storage and use laser technology to read the disc. But the DVD uses a red laser to read the disc, which works at 650nm of wavelength. On the other hand, Blu-ray discs work on blue laser, which works on a shorter wavelength or 450nm. It means it can read information more precisely and closely.
  • Disc Construction
    Both Blu-ray and DVDs look identical by naked eyes. The disc diameter of both discs is 120 mm, and it also has the same thickness of 1.2mm. Blu-ray discs are much scratch-resistant compared to the DVD.
  • Security
    The Blu-ray discs are much secured compared to the DVDs.

    • Comparison chart between Blu-ray and DVDs

    Blu-rays

    DVD

    A Blu-ray is an optical disc format to store different types of data, including videos.

    A DVD is also an optical disc storage format that can store different types of data that can be used on a computer.

    The storage capacity of the Blu-ray disc is about 25 GB of data for a single-layer disc. The double-layer disc can contain storage data up to 50 GB.

    A standard DVD can store up to 4.7 GB of data. The double-layer DVD can store up to 9 GB of data. Clearly, the data storage capacity of DVDs is much smaller than Blu-ray discs.

    These discs cost a little more compared to DVDs.

    The DVDs are cheaper than Blu-ray discs.

    Since it can store a large amount of data, hence it can contain more videos and allows to provide high-quality video and audios.

    Due to low storage capacity, it cannot have HD video quality on a DVD. It can only have SD (Standard Definition) data.

    Blu-ray is the modern technology than DVD, hence the old movies still not available in the Blu-ray format.

    DVDs are available since the year 1996; hence almost all the old and new movies are available in DVD formats.

    The 3-D movies are available on Blu-ray discs.

    The latest 3-D movies are not available in DVD format.

    The data transfer rate is much high compared to DVD, and of 36Mbps for data and 54Mbps for audio/video.

    The data transfer rate is much less compared to Blu-ray, and of 11.08 Mbps for data and 10.08 Mbps for video/audio.

    It provides high data security.

    The data security is less.

    It uses a Blu-ray laser of 405 nm wavelength.

    It uses a red-rays laser of 650nm wavelength.

    The numerical aperture (NA) of Blu-ray is 0.85.

    The numerical aperture (NA) of the DVD is 0.60.

    The video codecs available in Blu-ray disc are MPEG-2, MPEG-4, and SMPTE VC-1.

    The video codec available on DVD is MPEG-2.

    It is best suitable for storing large data such as shooting videos.

    It is best suitable to store a small amount of data, such as a movie.

    It contains a hard coating.

    It does not contain a hard coating.

    It uses a protection layer of 0.1mm.

    It contains a protection layer of 0.6mm.

    Conclusion

    As per the above discussion, it is clear that Blu-ray provides high data storage, high-definition quality videos, security, and compatibility compared to a DVD disc. But for all these reasons, are all discs useless? So, the answer is not yet. DVDs are much cheaper than Blu-rays, so if you do not care much about picture quality and want to spend less amount of money, then DVDs are a good option. DVDs can be played in DVD players, and also Blu-ray players, whereas Blu-ray can only be played using Blu-ray players, so this is also one fact that needs to be considered.