As digital cameras and camcorders become more advanced and capable of recording still and video content at higher pixel and colour resolutions, SD™ and CFexpress® card formats have grown in capacity, speed ratings, and data transfer capabilities.
That's why it's important to understand the requirements of your device and match it to the proper memory card. It's also interesting to consider the post-production of video content on computers when purchasing memory cards.
The following charts provide the complete video specifications for SD, SDHC™, SDXC™, and CFexpress cards. The charts are arranged to show information for the Normal and Slow & Quick record modes of your device as applicable. Check your product manual for the exact capabilities.
You can also refer to the SD Association website for more detailed explanations of SD card types.
Video format chart definitions
- Format - Each video file contains two elements: A CODEC (compression-decompression) program that compresses the video, and the format that the file is compressed to. Compression examples include H. 264, HEVC, while format examples include MKV, AVCHS, MP4.
- Resolution - The total number of pixels displayed on the screen and in each individual frame. Full high-definition is defined as 1920 x 1080 pixels while 4k is 3840 x 2160.
- Long Group of Frame (GOP) vs. Intra-frame Compression - Long GOP compression is when only certain frames are recorded individually. When frame data does not change, then the frame is not recorded. Intra-frame compression records each frame independently of the others.
- Long GOP will provide shorter file sizes, less resolution, and are more difficult to edit on a computer while Intra-frame creates large file sizes, better resolution, and are handled much easier when editing on a computer.
- Capture frames per second (fps) - How many video frames are captured per second. For example, 30 fps means the camera captures 30 frames per second. The higher the fps, the smoother the video will be. This is an important part of slow-motion recording.
- Record frames per second - How many video frames the device is capturing per second and producing as a recording. So 24 fps means that the camera is recording 24 individual frames in one second and when played back, it is one continuous video.
- Sampling rate/Bits - The sampling rate (Chroma sub-sampling) allows the reduction of the colour information in a signal to reduce bandwidth without significantly affecting picture quality. A 4:4:4 sampling rate has no compression, while 4:2:0 has a quarter of the information available.
For example, when you connect a computer to a TV, you might note some blurriness in the text that is less noticeable when viewing videos and photos. 8-bit colour allows a representation of 256 shades of each of the RGB (red, green, blue) colour spectrum for a total of 16.7 million combinations, while 10-bit colour allows 1,024 shades of each of the RGB colors for a total of 1.07 billion combinations. For those that value colour, this can be a significant specification.
- Data rate - The amount of data encoded (converted) per second when shooting a video. The higher the bit rate, the higher the quality of the video. The trade-off is larger file sizes.
- Memory card types- SDHC (high capacity) cards can store up to 32 GB of data while SDXC (extended capacity) cards can store up to 2 terabytes (2000 GB) of data. Older devices may not be able to use the SDXC cards and newer devices may require the higher capacities that SDHC cards do not have. CFexpress cards are newly introduced to certain cameras and provide higher speed capabilities.