Well after a long time my MTNL 1Mbps plan started working exactly as it should. Speedtest constantly showed 1Mbps or more. All downloads, whether from websites or torrents were consistently speeding along at 120kbps.But was miffed that 720p videos still would never stream without buffering and 480p would only occasionally work. The key reason I upgraded my broadband plan was to be able to watch streaming video in higher quality. However that didn't seem to be happening. I have read of users streaming 720p stutter free on 1mbps plans on this forum. So decided to do a little research.The methodology: Used the Download Helper plugin for Firefox on various videos on Youtube to determine the size of the mp4 or flv file being streamed. Collected the file sizes for various videos of different lengths when downloaded in all resolutions, i.e. 1080p, 720p, 480p, 360p and 240p. Fed the data into excel. Below are the results. The size per min values are averages of values recorded across videos. The variation in file sizes is not significant by and large, but in certain cases can vary by 20% odd percent(depending on bitrate). The 360p values are also consistent with files sizes for Megavideo streams. Its generally 85MB for a 20 minute sitcom video on Megavideo (which is 4.5MB per minute). So I work with the assumption Youtube values should apply for other streaming sites as well.
[TD="align: right"]1080[/TD][TD="align: right"]25[/TD][TD="align: right"]3.41[/TD][TD="align: right"]4.27[/TD][TD="align: right"]426.7[/TD][TD="align: right"]3.4[/TD]
[TD="align: right"]720[/TD][TD="align: right"]15[/TD][TD="align: right"]2.05[/TD][TD="align: right"]2.56[/TD][TD="align: right"]256.0[/TD][TD="align: right"]2.0[/TD]
[TD="align: right"]480[/TD][TD="align: right"]6[/TD][TD="align: right"]0.82[/TD][TD="align: right"]1.02[/TD][TD="align: right"]102.4[/TD][TD="align: right"]0.8[/TD]
[TD="align: right"]360[/TD][TD="align: right"]4.5[/TD][TD="align: right"]0.61[/TD][TD="align: right"]0.77[/TD][TD="align: right"]76.8[/TD][TD="align: right"]0.6[/TD]
[TD="align: right"]240[/TD][TD="align: right"]2.3[/TD][TD="align: right"]0.31[/TD][TD="align: right"]0.39[/TD][TD="align: right"]39.3[/TD][TD="align: right"]0.3[/TD]On average a 1 minute 1080p video has a file size of 25MB. On my 1Mbps connection's theoretical speed of 125kbps it equates to 3.41minutes. But since we can realistically expect our connections to give only 80% of its bandwidth consistently at best, the actual time to play a 1min 1080p file on a 1mbps plan increases to 4.27mins.So the theoretical speed required to seamlessly play a 1080p stream is 426kbps or 3.4Mbps connection. And a 720p will require a 2Mbps connection. In reality the connection will have to be faster.On my 1mbps it seems that only 480p is playable at best. But in reality that too doesn't happen all the time. Because the file sizes are averages. In reality depending on bit rate and overall quality of encoding the file sizes can vary and your speed will be only 80% on average and as such 480p's also don't work each and every time. But a very short pause and buffer before each 480 video and it continues very well. So as it turns out the 1Mbps plan can still play only 360p files seamlessly on the fly. That's something that my 752kbps plan also did very well. I have gained little benefit from the upgrade. In terms of browsing the difference of additional bandwidth is negligible. Of course the added speed helps other downloads, but am not much of a downloader and don't mind waiting the additional time a 0.75mbps connection would take (am sure there are many other applications for the increased bandwidth but I myself haven't really come across any scenarios practically yet where it helps a lot).This post is largely because I couldn't find any real info which linked bandwidth requirement to video streaming quality. Hope this information helps anyone looking to select a correct broadband plan. Cheers!
| Quality | Size per min | Theoretical Time | Act Time | Speed Req | Mbps |
