Video Codec: The Core Tool for Compressing & Transmitting Video in Conferences

1. Core Definition

A Video Codec (short for "coder-decoder") is a critical tool for processing video through two key steps: compression and decompression. Its role is to solve the "massive data transmission" problem in video conferences:

• Compression: Raw video data is extremely large (e.g., uncompressed 1080P video requires ~1.5 Gbps of Bandwidth per second—far exceeding the capacity of ordinary home or enterprise broadband). The codec reduces this data volume to a manageable size (often 1/100 to 1/500 of the original) by removing redundant information (e.g., repeated pixels in consecutive frames).
• Decompression: At the receiving end, the codec restores the compressed data back to a clear video image, ensuring participants see smooth, high-quality content.

Without a video codec, high-definition (HD) or ultra-high-definition (UHD) video conferences would be impossible due to Bandwidth limitations.

2. Mainstream Video Codecs & Their Application Scenarios

Currently, two codecs dominate video conference scenarios—each tailored to different quality, Bandwidth, and device compatibility needs:

2.1 H.264 (AVC: Advanced Video Coding)

H.264 is the most widely used codec in video conferences, valued for its balanced performance and universal compatibility.

• Key Advantages:
  • Strong Compatibility: Nearly all devices (computers, mobile phones, hardware conference terminals—even older models) support H.264 decoding, eliminating "audio plays but no video" or "blurry playback" issues.
  • Balanced Compression Efficiency: For 1080P Resolution (the mainstream for daily meetings), H.264 compresses video to a Bit Rate of only 2–4 Mbps—easily supported by most home broadband (≥10Mbps) or corporate intranets.
• Applicable Scenarios:
  • Ordinary small-to-medium meetings: Enterprise weekly department reviews, client communication calls, or team progress updates.
  • Meetings with mixed old and new devices: For example, a company where some employees use 5-year-old laptops and others use new mobile phones—H.264 ensures all can view content smoothly.
• Practical Example: An Internet company holds a 15-person product requirement meeting. The team shares 1080P PPT demonstrations encoded with H.264:
  • Employees joining via old desktops, new laptops, and mobile phones all load the video without stuttering;
  • The Bandwidth usage stays at 3–4 Mbps, leaving room for other office tasks (e.g., file transfers) without network congestion.

2.2 H.265 (HEVC: High Efficiency Video Coding)

H.265 is a next-generation high-efficiency codec that addresses the Bandwidth demands of ultra-high-definition (UHD) content.

• Key Advantages:
  • 50% Bandwidth Savings: At the same image quality, H.265 uses half the Bandwidth of H.264. For example:
    • 4K Resolution (critical for detail-heavy scenarios) requires only 4–6 Mbps with H.265, whereas H.264 would need 8–12 Mbps.
  • Better UHD Performance: It preserves fine details in 4K/8K video (e.g., tiny text in documents, subtle edges in medical images), making it ideal for professional scenarios.
• Applicable Scenarios:
  • Remote Medical Consultations: Primary hospitals with limited Bandwidth (e.g., 5–10 Mbps) need to transmit 4K CT/MRI images. H.265 ensures doctors can clearly see lesion edges and tissue details without Bandwidth overload.
  • Architectural/Industrial Design Reviews: Design teams share 4K drawings (e.g., building blueprints, PCB circuit boards). H.265 lets participants zoom in to check line dimensions or component labels without stuttering.
• Key Limitation:
  • Higher device performance requirements: Older devices (e.g., mobile phones with Android 6.0 or below, pre-2018 laptops) may struggle to decode H.265 smoothly, leading to playback lag or freezing.

3. Codec Selection Recommendations

To choose the right codec, focus on three factors: meeting Resolution, Bandwidth conditions, and device compatibility:

• Choose H.264 if:
  • Your meeting uses 720P/1080P Resolution (ordinary daily meetings);
  • Participants use mixed old and new devices;
  • Bandwidth is sufficient (≥10Mbps) and compatibility is a priority.
• Choose H.265 if:
  • Your meeting requires 4K/8K Resolution (professional scenarios like medical consultations or design reviews);
  • Bandwidth is limited (e.g., remote branches with 5–8 Mbps);
  • All participants use mid-to-high-end devices (post-2018 computers, 5G mobile phones) that support H.265 decoding.

In summary, H.264 remains the "safe, universal choice" for most enterprises’ daily meetings, while H.265 is the optimal solution for professional UHD scenarios or Bandwidth-constrained environments.