hd with x264 codec

[carlo_0000]

hy

i have a question

all my hd videos are in mpeg2 (1080i) 25fps (files are to big but had avantage that can be played easly on my celeron666)

so i tested a lot of time to convert it to x264

my question is : what is the minimum bitrate for HD mpeg4 (x264 here) 6000 ? 8000 ? to keep the full qualtiy of my mpeg2 (what have a average bitrate of 18000)

but there is a probleme my computer (athlon64 2800) can't play x264 video abouve 1152* with 8000kbps

so (if it is possible) converting them to 720p 50fps (same bitare +- 6-8000) does i have the same quality than a 1920* @25fps ?

or if i choose 1152* 25fps what bitrate must i use to keep full quality ?

or is it beter that i wait befor converting them

[thuongshoo]

my question is : what is the minimum bitrate for HD mpeg4 (x264 here) 6000 ? 8000 ? to keep the full qualtiy of my mpeg2 (what have a average bitrate of 18000)
oh ! my question is too . I also want to know how capacity of x264 is because I often don't resize and want to have orginal quality

[Blue_MiSfit]

so i tested a lot of time to convert it to x264

Yep. Encoding HD H.264 is a VERY slow proposition, especially with a nice crunchy deinterlacer :D


what is the minimum bitrate for HD mpeg4 (x264 here) 6000 ? 8000 ? to keep the full qualtiy of my mpeg2 (what have a average bitrate of 18000)

Like any other bitrate related question, this totally depends on the source. Start with 1/2 reduction and work your way down or up, that's usually what I do.


but there is a probleme my computer (athlon64 2800) can't play x264 video abouve 1152* with 8000kbps

This is dependant on a couple of things
1) Decoder
CoreAVC is the fastest decoder ATM, but you have to buy it. It's well worth it. The best free decoder is libavcodec (ffdshow). It can't do full 1080i on my system without dropping frames though.

2) Renderer
Overlay mixer is generally the fastest. Other options (VMR7, VMR9) may look a bit sharper, but are much slower at HD resolutions.

3) Encoding options
CABAC adds significant computational overhead, both on the decoder and encoder side. It does improve compression a lot, but for HD I would reccommend disabling it. CABAC+1080i was a nightmare for even CoreAVC on my system!


so (if it is possible) converting them to 720p 50fps (same bitare +- 6-8000) does i have the same quality than a 1920* @25fps ?
or if i choose 1152* 25fps what bitrate must i use to keep full quality ?

Going from 1080i50 to 720p50 will involve loss of information. Quite a bit of information actually. So no, you will not ever have the same quality. It may look pretty darned good though :) Again, the bitrate depends on the source and your eyes. You just have to experiment. Denoisers help. Also, downsizing and deinterlacing is a complex issue. Research a lot about this.


or is it beter that i wait befor converting them

Not sure what you mean here.

Just a friendly suggestion, a quick proof-reading of your posts really helps to ensure your understandability. Spell check is your friend :) No worries though, you got your point across.

Good luck
~MiSfit

[SeeMoreDigital]

all my hd videos are in mpeg2 (1080i) 25fps (files are to big but had avantage that can be played easly on my celeron666)Sadly I don't think you will be able to play 1920x1080 MPEG-4 AVC encodes on your PC.... Even at comparatively low bit-rates!

[rumpleforeskin]

encoding to 720p does indeed involve the loss of alot of quality but it still does look fantastic. and if you have a 720 HD tv that you are watching the movie on you will only see 720 lines anyway.

I have been encoding my .TS files to 720 for playback on my projector and trying to fit the movie to a single DVD. The bitrare required for this size results in a picture that is pleasant to the eye and not taking up too much room ( the idea of compression right :) )

but if you intend keeping the movies for the future when you have better displays maybe its best not to reencode at all

[carlo_0000]

Sadly I don't think you will be able to play 1920x1080 MPEG-4 AVC encodes on your PC.... Even at comparatively low bit-rates!


i have more than 1 pc ( just for saying that is is possible to play it on a slow computer

1920x1080 MPEG-4 AVC it s for my athlon64 2800



thanks for the aswers but i think i go keeping them to mpeg2 , don't like to loast to much quality end than they are only playable on my fastest computer

i olso tryed it to convert them to 720p 25 to 50 fps but it can't movie play faster than the audio stream