Video file types and resolution

[kibescorp]

This is actually a two part question relating to the same topic ... system resources (CPU usage) during playback of video files.

The first concern relates to different video file types.

Certain file types offer better data compression than others (from personal experience, it would seem that the old MPEGs were the least compressed, while the f4v flash video format seems to be highly compressed).

Well, assuming that you had TWO video files of the same exact video (meaning same length, same framerate, same resolution, etc.) ... but one was encoded as an MPEG file and the other an mp4 file (which offers much greater data compression).

So the mp4 file takes up much less space than the MPEG file, despite the fact that they are essentially the same video.

When playing them on a media player on your computer ... which will require more CPU and which will use less? Or would they essentially be the same, considering the framerate and resolution are the same? Would the larger file size use more system resources to playback the video or not?
The second concern relates to watching videos in their native aspect ratio (1:1) versus stretching them out to fullscreen.

Say you have TWO video files of the same exact video again (this time, same length, same framerate, and same file type). However, the difference this time is in the RESOLUTION. One video is rendered in 360p ... while the other is in HD (720p). The HD video file is exactly the same as 360p video ... except when it comes to resolution.

Assuming that your computer monitor has a native resolution of 720 vertical pixels ... then if you played back BOTH files using a media player ... which would use up more CPU (system resources) ... the 360p video in FULLSCREEN (meaning it is upscaled from 360 to 720) or the 720p video in its native resolution (which would fill up the whole screen automatically anyway in a 1:1 aspect ratio).

In other words, which uses more CPU ... having to upscale the 360p video so that it is now displaying in 720p ... or simply playing back the 720p video (automatically fullscreen), which is larger in size and contains more data than the 360p video to begin with?

Seems to me like if watching the 360p video in fullscreen uses the SAME amount of CPU as watching the 720p video normally ... then you're basically getting ripped off by watching a lower-resolution version of the same video ... upscaled (and poorly), are you not? The 360p video would look poor (needless to say) in fullscreen, while the 720p would look perfect in its native resolution ... and you'd still be straining your computer the SAME amount in either case ... total gyp. Or would playing the 360p video in fullscreen actually use MORE CPU ... because now the computer has to figure out how to fill in the missing pixels (and again, quite poorly)?

So what's the benefit (if any) of watching a lower-resolution version of the video? Simply that it conserves HDD space?

In addition, in the above example ... when you are stretching out the 360p video to fullscreen view ... which device is actually doing the upscaling? Is it the COMPUTER or the MONITOR that is doing the work? When you watch standard definition video on an HDTV, 90% of the time the TV is the one doing the upscaling ... however, on a computer it's the computer and not the monitor that actually does the upscaling, correct?

[MilesAhead]

A lot would depend on the codec used to decompress the video. Also some players can use the GPU instead of the CPU depending on your video card(CUDA is one system.)

If it's just as easy to use .mp4 as .mpg I would try a bunch of players that can play the .mp4. SPlayer portable is one that can use GPU and plays HD formats well. I recommend the portable rather than installed because there was a problem with file type associations and the installed version. Could be fixed but for me there's no benefit to associating the file type anyway. I put a shortcut to portable SPlayer in my SendTo folder. I can play any supported file by right clicking and choosing SPlayer from SendTo.

The other consideration is if you have to mess with subtitles. WMP 12 and VLC have PGS subtitle support. SPlayer doesn't. Subtitles tend to complicate things. I would just try a bunch of portable .mp4 players and see which ones you like.

The newer versions of VLC support just about every format and would do just about everything well if they didn't crash. Your mileage may vary but it seems on Windows Seven every version of VLC from 1.0 on crashes as soon as I touch it when I'm playing a video. Just about useless when it used to be the best and most versatile. Instead of adding codecs they should get it to allow use of the controls while a video is playing. Touch it and it goes away is bizarre to say the least.

[admin]

Typically, a more efficient codec (eg. H.264 vs MPEG-2) would require more processing power to both encode and decode - compression is really just mathematical calculations (lots of them!), and the more efficient codecs use more complex calculations, which require more CPU/GPU cycles.

It holds true for increased resolution of the video as well, as it simply means more data to process.

Scaling depends on how the scaling algorithm was written, as that will determine CPU load and also memory. Scaling can be done on the display (if you're not using the native resolution of the monitor), or it can be done on the computer (or both - eg. upscaling a 360p video to a Windows resolution of 720p and outputting to a 1080p monitor - Windows scales from 360p to 720p, and the monitor scales from 720p to 1080p).

A lot of this is done in hardware (GPU) these days or accelerated by instructions on the CPU (eg. Intel SSE3), so you might not notice any difference, performance wise. There are impacts quality wise of couse. For Blu-ray, for example, you'll always want to set your Windows resolution to 1080p (or higher) and set the resolution at the native resolution of the display device.

[kibescorp]

Thanks for the replies. So basically ... even if the same video was compressed more to take up less space, it wouldn't necessarily use less system resources during playback ... than if it hadn't been compressed? Also, I have a 1366x768 monitor, but that's also what I have my display settings set to. So I can conclude then that the computer is doing all of the upscaling and not the monitor?

[admin]

On the first question, yes, but it really depends on the codec, and what kind of hardware acceleration you have. The second question, also yes, only the computer would be doing the scaling if you've set the desktop resolution to the same as your monitor's native resolution.

[Adrian12354]

This is actually a two part question relating to the same topic ... system resources (CPU usage) during playback of video files.

The first concern relates to different video file types.

Certain file types offer better data compression than others (from personal experience, it would seem that the old MPEGs were the least compressed, while the f4v flash video format seems to be highly compressed).

Well, assuming that you had TWO video files of the same exact video (meaning same length, same framerate, same resolution, etc.) ... but one was encoded as an MPEG file and the other an mp4 file (which offers much greater data compression).

So the mp4 file takes up much less space than the MPEG file, despite the fact that they are essentially the same video.

When playing them on a media player on your computer ... which will require more CPU and which will use less? Or would they essentially be the same, considering the framerate and resolution are the same? Would the larger file size use more system resources to playback the video or not?
The second concern relates to watching videos in their native aspect ratio (1:1) versus stretching them out to fullscreen.

Say you have TWO video files of the same exact video again (this time, same length, same framerate, and same file type). However, the difference this time is in the RESOLUTION. One video is rendered in 360p ... while the other is in HD (720p). The HD video file is exactly the same as 360p video ... except when it comes to resolution.

Assuming that your computer monitor has a native resolution of 720 vertical pixels ... then if you played back BOTH files using a media player ... which would use up more CPU (system resources) ... the 360p video in FULLSCREEN (meaning it is upscaled from 360 to 720) or the 720p video in its native resolution (which would fill up the whole screen automatically anyway in a 1:1 aspect ratio).

In other words, which uses more CPU ... having to upscale the 360p video so that it is now displaying in 720p ... or simply playing back the 720p video (automatically fullscreen), which is larger in size and contains more data than the 360p video to begin with?

Seems to me like if watching the 360p video in fullscreen uses the SAME amount of CPU as watching the 720p video normally ... then you're basically getting ripped off by watching a lower-resolution version of the same video ... upscaled (and poorly), are you not? The 360p video would look poor (needless to say) in fullscreen, while the 720p would look perfect in its native resolution ... and you'd still be straining your computer the SAME amount in either case ... total gyp. Or would playing the 360p video in fullscreen actually use MORE CPU ... because now the computer has to figure out how to fill in the missing pixels (and again, quite poorly)?

So what's the benefit (if any) of watching a lower-resolution version of the video? Simply that it conserves HDD space?

In addition, in the above example ... when you are stretching out the 360p video to fullscreen view ... which device is actually doing the upscaling? Is it the COMPUTER or the MONITOR that is doing the work? When you watch standard definition video on an HDTV, 90% of the time the TV is the one doing the upscaling ... however, on a computer it's the computer and not the monitor that actually does the upscaling, correct?

thanks for sharing this....