Origin Digital goes HD
Here at Origin Digital, we are frequently asked to explain just what HD, or high definition, means in the online world. The conversation normally starts when the client asks for a “widescreen” player size (16:9 aspect ratio) which has become popular on social media sites such as YouTube who recently switch their default player to widescreen. This is also driven by the explosion of HD television sets in the home, and the closer fit of the widescreen format to our vision (we see in wide screen). HD online is actually more about making that content accessible to everyone versus making sure they can view it at the same quality as on their TV. HD online can be examined using the following characteristics:
• Source format
• Aspect ratio
• Encoding bit rate
• Video size (height by width)
Source Format
As with all video, the available options for outputs are going to be largely driven by what was used to capture the video in the first place. As far as HD goes, there are two camera resolutions, 1280x720 (aka 720) and 1920x1080 (aka 1080). The “i" or “p” denote whether or not the frames of the video are interlaced, where each frame has only 50% of the detail that is flipped back and forth so that the eye perceives a full image, or progressive which displays full detail for each frame. Progressive is how desktop/laptop monitors display video, so anything that is to be displayed on the PC that isn’t progressive must be ‘de-interlaced’. In all instances, it is better to film in progressive if you can.
Aspect Ratio
Aspect ratio for HD is typically 16:9; others are available (16:10, 2.XX:1), but this is the most common. However, even if you filmed content in standard definition, you can still display your video in a widescreen player. This can be done in one of three methods; by having the player display black in the background on the left and right, encoding the video using pillarboxing, or stretching the video until the left and right edges are flush then cropping the top and bottom.
Encoding Bit Rate
HD doesn’t always have to be super high quality to give the end user a good experience. Although broadband has proliferated, not everyone can view 6-8 mbps video. As with all video online, it is important to give the user choices, or use one of the newer adaptive bit rate technologies to make that choice for them. A 16:9 formatted video can be as low as 300 kbps (with the correct corresponding size) or greater than 8 mbps. A ‘good’ top bit rate for HD, however, is anything over 1.5 mbps. This gives a good compromise between accessibility and viewability – especially when delivered over HTTP.
Video Size
Player size corresponds to the bit rate; as your bit rate decreases, so should your video size and vice versa. Players can either display video in a smaller area surrounded by black, or stretch the video to fit (up or down). As interactive options increase outside of the video player (real time feeds, chat, synchronized content, other viewing angles), more and more people are viewing content within a web page as opposed to increasing it to full screen like traditional TV viewing. This further decreases the need for pristine 720/1080 video sizes and bit rates.
You should always consider your audience and how they are consuming your content. If it is a high profile sporting event, then you probably want to push up the bit rate and video size as close to TV as possible. If it is enterprise content, then take advantage of the HD widescreen format but keep your video accessible for those on slower corporate networks as well as provide high quality options for work from home and external users. However, having the widescreen size available as your default player size is ideal as it will encourage people to shoot in HD while still maintaining backwards compatibility with legacy content in standard definition.
Author - Forest Johns, VP of Solutions Engineering
• Source format
• Aspect ratio
• Encoding bit rate
• Video size (height by width)
Source Format
As with all video, the available options for outputs are going to be largely driven by what was used to capture the video in the first place. As far as HD goes, there are two camera resolutions, 1280x720 (aka 720) and 1920x1080 (aka 1080). The “i" or “p” denote whether or not the frames of the video are interlaced, where each frame has only 50% of the detail that is flipped back and forth so that the eye perceives a full image, or progressive which displays full detail for each frame. Progressive is how desktop/laptop monitors display video, so anything that is to be displayed on the PC that isn’t progressive must be ‘de-interlaced’. In all instances, it is better to film in progressive if you can.
Aspect Ratio
Aspect ratio for HD is typically 16:9; others are available (16:10, 2.XX:1), but this is the most common. However, even if you filmed content in standard definition, you can still display your video in a widescreen player. This can be done in one of three methods; by having the player display black in the background on the left and right, encoding the video using pillarboxing, or stretching the video until the left and right edges are flush then cropping the top and bottom.
Encoding Bit Rate
HD doesn’t always have to be super high quality to give the end user a good experience. Although broadband has proliferated, not everyone can view 6-8 mbps video. As with all video online, it is important to give the user choices, or use one of the newer adaptive bit rate technologies to make that choice for them. A 16:9 formatted video can be as low as 300 kbps (with the correct corresponding size) or greater than 8 mbps. A ‘good’ top bit rate for HD, however, is anything over 1.5 mbps. This gives a good compromise between accessibility and viewability – especially when delivered over HTTP.
Video Size
Player size corresponds to the bit rate; as your bit rate decreases, so should your video size and vice versa. Players can either display video in a smaller area surrounded by black, or stretch the video to fit (up or down). As interactive options increase outside of the video player (real time feeds, chat, synchronized content, other viewing angles), more and more people are viewing content within a web page as opposed to increasing it to full screen like traditional TV viewing. This further decreases the need for pristine 720/1080 video sizes and bit rates.
You should always consider your audience and how they are consuming your content. If it is a high profile sporting event, then you probably want to push up the bit rate and video size as close to TV as possible. If it is enterprise content, then take advantage of the HD widescreen format but keep your video accessible for those on slower corporate networks as well as provide high quality options for work from home and external users. However, having the widescreen size available as your default player size is ideal as it will encourage people to shoot in HD while still maintaining backwards compatibility with legacy content in standard definition.
Author - Forest Johns, VP of Solutions Engineering
posted by Origin Digital at
9:28 AM
2 Comments:
So, what actual *player size* and encode size (pixels) are you recommending, along with the 1.5mbps bitrate.
A popular size lately has been 640 x 360 at the lower bitrates (500-1000 kbps), however, at >1 mbps you could do 869x504, 960x540 or 1024x576. At >2.5 mbps you can start going to 1280x720. This of course will vary with your content. Fairly static content like talking heads, etc. will encode really well even at lower bit rates because of the repetition of content, however, full motion sports footage will strain the compression to the maximum. Play around and select the size/bit rates that work for you.
Forest
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