H.264 (mp4/m4v) tips

H.264 is a standard for video encoding for online distribution. It’s also the most used for video podcasting using the .mp4 or .m4v file extension. You can use H.264 to encode other types of video files, but for podcast use, it’s best to stick with .mp4 or .m4v.

MP4 is very close to Apple’s Quicktime format with some added features.

  • M4V is Apple’s slightly different version of MP4 for iTunes
  • MOV is Quicktime format

We recommend you use MP4 as it is the most widely compatible file format.

For more information on the different video formats, see: Video Formats

Common video sizes in use for podcasting and online streaming sites like YouTube are:
640×480 – Standard Definition 4×3 aspect ratio
960×640 – Standard Definition 4×3
1024×768 – Standard Definition 4×3
640×360 – Standard Definition 16×9 Wide Screen
1280×720 – High Definition 16×9 Wide Screen (otherwise known as 720p)
1920×1080 – High Definition 16×9 Wide Screen – ** not in use as much but will be in the future – Also REALLY large files
Any of these sizes will work nicely for your podcast video (the higher the better in most cases)


It is important that you have your file setup for streaming. This way it will start playing after buffering a short time inside of the Flash or html5 players on your page.

When you encode your video file, it needs to be setup for streaming for it to “progressively download” and play while downloading. Settings to look for in your video encoding software are things such as “hinted streaming”, “adaptive steaming” or just “streaming” in the output settings. There is some meta data in the file that are called Atom tags. These tags need to be in the front of the file to make the file stream while the file is downloading.

Here are a few programs that will fix the meta tags in your file if your encoding software doesn’t put the tags at the front of the file:

Video media file hosting tips

  • Don’t use free services such as Archive.org for newly released episodes. Free services do not guarantee delivery of large media like a paid Content Delivery Network (CDN) would and they will throttle/kill excessive downloads rather than host your media for free.
  • Do not host your media on the same server as your website. The large media file downloads can cause your website to come to a crawl the first few hours your episodes are released.
  • Make sure your Web server reports the correct content type for your media file. Mp4 should report as Content-Type “video/mp4.” This is typically not a concern, but can explain why the media file does not play in the computer’s default media player when downloaded.
  • Always make sure your files have the appropriate file extensions (e.g. file.mp4), iTunes and many other applications determine the file content type based on the file extension.
  • Only use the 26 English letters, 0-9 numbers and underscore/dash characters for file names and folders. Some applications will not capture the special characters, such as dollar signs or commas, correctly from the file name, which could make the saved file unplayable on the target device.
  • Never use spaces in your files and folders (same reason as above).