Panoramic Review of Camera Video Color Coding Formats: All-Intra vs Long GOP Compression Efficiency and Non-Editorial Performance Comparison

1. The essence of digital video compression: elimination of time and space redundancy

Modern cameras record 4K 60P 10-bit video. Without any data compression, the amount of uncompressed RAW data generated per second is as high as more than 1.5GB. A 128G memory card will be completely exhausted in more than a minute:

1. Two core directions of compression:

• Spatial Redundancy (Intra-Frame): The colors of adjacent pixels within a single picture are highly similar (such as blue sky) and can be compressed and merged;
• Time Redundancy (Inter-Frame): In the 60 frames of continuous recording, the background tables and chairs often do not move at all, only the actors' lips move. There is no need to save the entire background repeatedly in every frame!

2. Long GOP (interframe prediction compression/IPB group) technical mechanism

The default high-efficiency compression format of mainstream consumer cameras (such as Sony XAVC S, Canon IPB, Panasonic LongGOP):

1. GOP - Group of Pictures) architecture:

• A typical GOP contains 12 to 30 frames, consisting of three different types of frames:
• I Frame (Intra-coded Frame/Key Frame): an independent basic frame that completely saves all the details of the entire photo;
• P Frame (Predicted Frame/Forward Predicted Frame): Referring to the previous I frame, only the motion vector of the displacement change in the picture and the prediction difference are recorded;
• B Frame (Bi-directional Frame/Bi-directional Predictive Frame): Extremely highly compressed frame, not only referring to the previous I frame, but also pre-reading the future P frame backwards, and only recording the bidirectional interpolation residual.

2. Advantages and Achilles’ Weaknesses of Long GOP:

• Ultra-high compression ratio advantage: The bit rate is usually only 100Mbps to 150Mbps, the file is very small, ordinary cheap V30 memory card can do the job, suitable for long-term meeting recording, event tracking and travel vlog;
• Image quality collapse under violent motion (Macro-blocking): When shooting full-screen high-speed and chaotic motion scenes such as fountain water, falling leaves, storms, and birds flying over, the time prediction algorithm completely fails, and the screen will instantly explode into large mosaic blocks and tearing artifacts;
• Torture of editing computer CPU: When dragging the play pointer on the editing software timeline, in order to display the 7th frame, the computer must forcibly decompress and calculate all the previous I frames and subsequent P frames in the memory, causing the timeline to freeze crazily and drop frames.

3. Pure film and television-level pedigree of All-Intra (Intra-frame encoding / All-I)

Industry benchmarks for professional cinema cameras and high-end mirrorless cameras (such as Sony XAVC S-I, Panasonic ALL-Intra 400M, Canon ALL-I):

1. Pure frame-by-frame completely independent encoding (All Frames are I-Frames):

• Completely abolish any cross-frame P-frame and B-frame prediction!
• Every frame in the video is an independent, complete, independent image of the highest quality without cutting corners!

2. Unrivaled Advantages of All-Intra:

• Impeccable high-speed dynamic image quality: No matter how fast the water splashes or how fast the camera pans, every frame has ultimate clarity and will never produce motion artifacts or block compression defects;
• Extremely smooth editing timeline (Blazing Fast Playback): The editing software drags the time pointer to any frame, and the CPU/GPU reads directly instantly, without the need for complex cross-frame reverse prediction calculations, and multi-camera real-time editing without lag;
• Price: Ultra-high bit rate and large storage overhead: All-I's bit rate is usually as high as 400Mbps to 800Mbps (equivalent to 4 to 6 times that of Long GOP), and it must be equipped with an expensive V90 SD card or CFexpress memory card, which eats up hard disk space very quickly.

4. Golden decision tree for actual selection in all scenarios

---