bit rate versus resolution

[topquark]

Hello. I am trying to download videos from Youtube and I am using both 1-click youtube video downloader (a firefox add-on) and the new realplayer downloader. I am a bit confused as to which one to use because the videos I download using them have different specs.

Using the firefox add-on, which downloads in mp4 format, i get larger-sized videos with higher bit rates, but lower screen resolutions and frames per second. The realplayer downloader downloads in flv format, which are smaller in size but have larger screen resolutions and better fps, but lower bit rates.

Basically, my question is, which one is better, the mp4 with the higher bit rate or the flv with the larger screen resolution and faster frame rates?

Here is a sample comparison:

VIDEO.FLV
size: 37.1 MB
display resolution: 540x360
frame rate: 59.940000
quality (bit rate): 568kbps

VIDEO.MP4
size: 42.1 MB
display resolution: 480x320
frame rate: 29.970029
quality (bit rate): 651kbps

I want to be able to transfer the files to a dvd later on. I'm really having trouble deciding which is better -- the higher resolution or the higher bit rate. And what about frame rate? Please please help. Which one is the better-quality video here?? Thanks a lot in advance.

[redwudz]

Generally, higher bitrates will make the most difference in quality. A Divx/Xvid video at 320 X 240 at 1000Kbps will generally look better than the same Divx/Xvid video at 720 X 480 at 500Kbps. But lots of variables. The major difference most times with bitrate concerns is the codec used. Some codecs, like H.264, are a lot more efficient than Divx/Xvid at high compression settings and may yield better quality that way. No idea about FLV. Framerate is a smaller factor in all this. More important with action videos.

But it can get more complicated than all that.

[topquark]

Thanks a lot for that, that helped but I'm still a bit confused. Here are the video codecs used for the files (according to vlc player):

MP4 - avc1
FLV - h264

I have no idea what those codecs are and what their difference is, but I hope that can help someone help me decide which video is the better-quality one.

[Gavino]

I hope that can help someone help me decide which video is the better-quality one.

The best way to judge 'quality' is to use your eyes.

[creamyhorror]

VIDEO.FLV
size: 37.1 MB
display resolution: 540x360
frame rate: 59.940000
quality (bit rate): 568kbps

VIDEO.MP4
size: 42.1 MB
display resolution: 480x320
frame rate: 29.970029
quality (bit rate): 651kbps

These are not the same video, unless the framerate information is incorrect. The first one is 60fps while the second is 30fps, so the first will have smoother motion but also require much more bitrate to look decent. I don't think Youtube has 60fps video, so I don't know how you got the first clip. (avc1 is the same as H.264, by the way.)

If both are the exact same video, I'm going to guess the second clip looks better overall despite the lower smoothness. But you should of course compare the videos personally. Converting to DVD format might complicate matters, and I don't know enough to comment on that.

[topquark]

Thanks for that info. It's the same video. The first one I downloaded using the new realplayer downloader, set at best quality. the second one I used a different downloader to get, but these are two different versions of the same video. Are you saying the one with the 60 fps is the better one?

What I really got confused about was the screen resolution. Up until this time I thought that larger screen resolutions meant better quality, but I really didn't get why the mp4, although it had a smaller resolution, had a larger size and better bit rate.

[creamyhorror]

"Best quality"? Throw that shit away, you don't want to capture and re-encode the video, you want to download the original!

1. Use a proper downloader (like Download Helper) that doesn't capture and re-encode the video.

2. Make sure you're viewing the best available format (720p where possible, 480p otherwise). Switch to the best format and let it load.

3. Use Download Helper to download it.

[jman98]

Resolution really has nothing to do with quality. Quality is all about bit rates. The lower the resolution, the lower the bit rate needed to make it look good, but note that enlarging a low resolution video will show the flaws in it. For example, you could have a video at 352x240 that would be pretty small on your PC screen but if encode with a high enough bit rate, at 352x240 in a small window it will look pretty good. If you blow that up to full screen, you will see a lot of artifacts that aren't visible at the normal resolution. All things considered, I would expect the 2nd video in your list to look the best. The frame rate is irrelevant to quality. The 2nd video has a smaller resolution and a higher bit rate. High resolution videos can provide amazing quality, but they require high bit rates to achieve it. They need significantly higher bit rates than your examples.

By the way, I've used the free StreamTransport program to successfully record some YouTube videos to my PC and I'm really pleased with it. For years you had to pay to get anything that worked that well. StreamTransport is a little tricky to get working at first, but once you get it working it's easy to use.