Understanding h.264 & h.265 Codecs

Understand the difference between h.264 and h.265 video compression and how to choose the right quality size for streaming

Updated over a week ago

Introduction

Today we will explore the difference in true quality media file sizes and point out the differences and limitations of h.264 and h.265 compressions.

Understanding the difference between codecs:

H.264 Codec.

H. 264 was designed to deliver good video quality at lower bitrates than previous standards, such as MPEG-4. Today, H.264 is popular across streaming providers mainly due to its high device compatibility.

  • Pro: It supports media containers like MP4, MOV, and more.

  • Pro: A server with decent resources can encode media with H.264.

  • Con: 4K H.264 files are limited to 60 fps (frames per second).

  • Pro: Almost any device today can play H.264.

H.265 Codec.

The H. 265 (HEVC) codec, on the other hand, provides much better compression rates than H.264. It lowers the bitrate to almost half while keeping the same video quality. This better compression rate results in far smaller files, requiring less bandwidth for transmission. On average, an H.264 compressed 4K media file would require 32Mbps bandwidth for smooth streaming, while the same 4K file compressed with H.265 would require 15 Mbps (less than half) bandwidth to stream it.

Required bandwidth for 4K

  • Pro: The difference in file size reduction with H.265, as compared with H.264 is 22% [source: 9to5mac].

  • Con: H.265 uses a complex codec mechanism. Decoding and encoding a file with H.265 will take a lot more computing resources, and it will be a much slower process than H.264.

  • Pro: H.265 compression allows resource-intensive resolutions such as 8K and a maximum frame rate per second of 300 fps. Obviously, as frame rates increase, so does the need for storage and bandwidth.

  • Con: Unfortunately, H. 265 is still not widely supported by devices and software.

Although it makes sense to stream a 4K media file compressed with H.265, since it would require less overall bandwidth and storage, for now, the overall compatibility across playback devices for H.265 is scarce. Plus, encoding content with H.265 HEVC will be a lot more difficult and time-consuming. Decoding H.265 requires high CPU or GPU, hardware resources.

If you intend to transcode your content, you are better off transcoding 4K H.264 content, not transcoding 4K H.265 content, due to the high computational demand. BUT, if all your playback chain is compatible with H.265, and your content is already H.265, then streaming with this codec is a much better solution.

**More information here**

True Quality Size:

When searching our favorite torrent sites, oftentimes we come across downloads with a great number of seeders with 1080p quality and a file size under 2GB.

Let’s use Harry Potter and the Goblet of Fire as an example. We’ll also use The Pirate Bay and NZBgeek as our indexers to view differences in qualities.

Results from TPB show a much smaller file size:

NZBgeek shows a larger TRUE quality file size.

*Most often, private torrent trackers and Usenet indexers will have actual quality over public torrent sites or trackers*

When choosing between file sizes, you have two things to consider:

  1. How much space do I have?

  2. How much do I care about true quality file size, and if TRUE 720p is equal to the file size of my current 1080p downloads, should I re-download?

The answer is completely up to you. However, it’s important to note the limitations of transcoding on your seedbox or local server.

As a minimum hardware requirement, Plex recommends having at least an Intel Core i3 (or equivalent) or a faster processor on the server side. However, an Intel Core i3 processor would not be capable of transcoding or attending to simultaneous streams, and definitely not 4K streams.

The following table from the complete guide to Plex describes the minimum requirements for streaming without transcoding to transcoding a single 4K media file.

Transcode

Minimum CPU

RAM

No Transcode

Intel “Atom” 1.2GHz

2GB

Single 720p transcode

Intel Core i3 3.0 GHz

2GB

Single 1080p transcode

Intel Core i5 3.0GHz

2GB

Single 2160p (4K) transcode

Intel Core i7 3.2GHz

2GB

As long as you are not transcoding 4K streams, you’ll do fine with an Intel Core i3. But if you want to transcode multiple streams or 4K videos your server will need a new level processor and help from GPU. An Intel Core i7 3.2GHz processor (or higher) is a good place to start for successful 4K transcoding.

If you’re interested in streaming 4K content from your seedbox, take a look at this guide HERE!

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