What is bit rate?

[lolzisgoodforu]

I tested 2 4k 5 minute videos with shadowplay and one of them with 30 bit rate and the other with 130 bit rate, 130 bit rate file took up way more storage than the 30 bit rate file did. yet when i play back to videos together i see little to no difference, so what even is bit rate?

[The Sloth]

google-http://help.encoding.com/knowledge-base/article/understanding-bitrates-in-video-files/

[mama_fluxus]

2 minutes ago, lolzisgoodforu said:

I tested 2 4k 5 minute videos with shadowplay and one of them with 30 bit rate and the other with 130 bit rate, 130 bit rate file took up way more storage than the 30 bit rate file did. yet when i play back to videos together i see little to no difference, so what even is bit rate?

Bit-rate is how much data is encoded into 1 second of video.

 

The 30 bit-rate is probably 30mbp/s and the 130 is probably 130mbp\s. Theretofore the 30 has been far more compressed (with a subtle loss of quality) than the 130. If you were to set the bit-rate to 5 you would see a drastic change and the video would look really bad but take up far less data.

[WereCat]

33 minutes ago, mama_fluxus said:

Bit-rate is how much data is encoded into 1 second of video.

 

The 30 bit-rate is probably 30mbp/s and the 130 is probably 130mbp\s. Theretofore the 30 has been far more compressed (with a subtle loss of quality) than the 130. If you were to set the bit-rate to 5 you would see a drastic change and the video would look really bad but take up far less data.

This.

 

Also the reason why you haven't seen much of a difference between 30 and 130 Mb/s bitrate recording is because using GPU for capture requires huge amounts of bitrate to get good quality video. The main difference you could probably notice is that there is less pixelation when image is in motion on the 130 vs 30 Mb/s bitrate due to less approximation in compression.

 

If you used H264 on your CPU to capture the video you would notice that you get much higher quality with much less bitrate this however has a lot more performance hit than the GPU capture.

With 30 Mb/s bitrate using H264 on CPU you would get much better quality than with 130 Mb/s using Shadowplay.

Also you could probably match the 30Mb/s Shadowplay quality with as little as 3-5 Mb/s bitrate using H264 resulting in much smaller files.

 

However I wouldn't recommend recording 4k with such low bitrate if there is motion. For desktop capture it is fine but for games I would advise at least 10Mb/s or 20Mb/s ideal for 30FPS capture.

 

Note that it matters how much FPS does the capture has. To get the same quality recording on 60FPS you need double the bitrate you would need on 30FPS.

Same goes for resolution. Recording 20Mb/s FHD gives you better quality than recording 20Mb/s 4k since 4k has 4x as much pixels. To get the same quality on 4k you would ideally want 4x as much bitrate (in theory, in practice the math works a bit different).

 

Therefore if you have capable CPU I highly recommend you using OBS instead of Shadowplay.

 

Edited for more info.

[lolzisgoodforu]

On 2/20/2017 at 11:13 PM, WereCat said:

This.

 

Also the reason why you haven't seen much of a difference between 30 and 130 Mb/s bitrate recording is because using GPU for capture requires huge amounts of bitrate to get good quality video. The main difference you could probably notice is that there is less pixelation when image is in motion on the 130 vs 30 Mb/s bitrate due to less approximation in compression.

 

If you used H264 on your CPU to capture the video you would notice that you get much higher quality with much less bitrate this however has a lot more performance hit than the GPU capture.

With 30 Mb/s bitrate using H264 on CPU you would get much better quality than with 130 Mb/s using Shadowplay.

Also you could probably match the 30Mb/s Shadowplay quality with as little as 3-5 Mb/s bitrate using H264 resulting in much smaller files.

 

However I wouldn't recommend recording 4k with such low bitrate if there is motion. For desktop capture it is fine but for games I would advise at least 10Mb/s or 20Mb/s ideal for 30FPS capture.

 

Note that it matters how much FPS does the capture has. To get the same quality recording on 60FPS you need double the bitrate you would need on 30FPS.

Same goes for resolution. Recording 20Mb/s FHD gives you better quality than recording 20Mb/s 4k since 4k has 4x as much pixels. To get the same quality on 4k you would ideally want 4x as much bitrate (in theory, in practice the math works a bit different).

 

Therefore if you have capable CPU I highly recommend you using OBS instead of Shadowplay.

 

Edited for more info.

ok thanks that is a crap load of information, but the thing is i dont have a very capable cpu, i have an i3 6100 so recording with obs would drop my frames quite a bit. another reason i use shadowplay is because of the backround recording thing so i can just hit a couple buttons and its records what happened in the last X amount of minutes.