How to 1080i to XVID 720p ?

[Prysme]

Hello,

I'm trying to find a way to resolve two issues in the same time
- reduce size of a 1080i stream
- deinterlace the "i" into a "p" offline in order to not have a overhead during the playback

My goal is to read the result on a HITACHI projector with a 720p matrix what ever the original fps, but I don't want to deinterlace at runtime during the playback.

After many tries with mencoder and plenty command lines, I am giving up ... I am really confused about those thing telecine, IVTC, deinterlace, decimate and so on ...
Each try gives me a jerky video (bad fps) or a ugly one (bad deinterlacing) ...

Let's take this example
ftp://ftp.heise.de/pub/ct/spezial/emotion.mpg

Could someone help me with this sample : 1080i to xvid 720p ?

Cheers,
Prysme.

[MrTroy]

Search the AviSynth subforum, there are numerous threads about this.

[Prysme]

Originally Posted by MrTroy

Search the AviSynth subforum,

I did it of course
But I don't have found a solution to my issues, that's why I am asking for an example with this sample.

Originally Posted by MrTroy

there are numerous threads about this.

Perhaps my topic has to be moved to the avisynth section, is there a moderator to do it?

[MrTroy]

OK, here you go.
First, make a .d2v out of your stream with DGIndex (there really ARE dozens of threads about that).

Then use this AviSynth script with your favourite encoder.

LoadPlugin("C:\Program Files\DGIndex\DGDecode.dll")
video=MPEG2Source("YourFile.avs")
ac3=NicAC3Source("YourAC3File DELAY -xxxms.ac3",channels=6).DelayAudio(-0.xxx)
wav=GetChannel(ac3,1,3,2,6,4,5)
AudioDub(video,wav)
DoubleWeave()
PullDown(0,3)
AssumeFPS(24,sync_audio=true)
SSRC(48000)
Crop(0,0,0,-8)
Spline36Resize(1280,720)

[blubberbirne]

I used this script

LoadPlugin("D:\DVDSoft\dgmpgdec\dgdecode.dll")
LoadPlugin("C:\Programme\AviSynth 2.5\plugins\TIVTC.dll")

MPEG2Source("file.d2v")
tfm().tdecimate()
Lanczos4Resize(1280,720,0,0,1920,1080)

Works perfect for me

[MrTroy]

Originally Posted by blubberbirne

I used this script

...

Works perfect for me

That script doesn't handle the audio, doesn't take care of the redundant 8px in 1080i streams and uses a resize method that's actually meant for upscaling instead of downscaling.

Needless to say, I think Prysme would do better using my script.

[dukey]

do reduceby2 or whatever it is
and encode it at 960x544
That will do a perfect deinterlace, although will be a bit lower resolution than 1280x720 .. but you wont notice much diff tbh

[scharfis_brain]

MrTroy: your script is not adaptive to floating pulldown patterns. It involves a 23.976 -> 24.000 fps audio speedup with audio recoding (which is always sub-optimal! especially with AC3). Spline32Resize() is not my favourite resizer. Lanczos does a pretty well job one downscaling IMO.

also blubberbirne's script takes care of the 1088 -> 1080 thing.

I'd prefer blubberbirnes script in the case of NTSC-Film, cause it leaves the audio as it is.

Of cause there are many other possibilitys how to deal with 1080i contents. The possibilities are the same like in the case of 480i or 576i.

[MrTroy]

Originally Posted by scharfis_brain

MrTroy: your script is not adaptive to floating pulldown patterns. It involves a 23.976 -> 24.000 fps audio speedup with audio recoding (which is always sub-optimal! especially with AC3). Spline32Resize() is not my favourite resizer. Lanczos does a pretty well job one downscaling IMO.

I have never come across a 1080i broadcast with floating pulldown. But you're correct of course: it IS possible.
As for the resizing: I did some comparative tests and I prefer Spline resizing for this job. Of course, that's just my preference.
You're correct that with this script, the audio has to be recoded. But myself I always recode the audio anyway: broadcast streams are 384kbps, not really suitable for making a reasonably small XviD.

also blubberbirne's script takes care of the 1088 -> 1080 thing.

Heh, stupid of me, I didn't see it.

[scharfis_brain]

Reencoding AC3 is nonsense if you want to make an HDTV AVI File, because why HD-Video and SD-Sound?

Also reencoding AC3 has some weird disadvatages like bit depth etc.
you need to decode AC3 with at least 24bit and then you need to encode with an encoder that accepts at least 24bits.
This is why AC3 can virtually store much higher bitdepths that 16bit.
SO with nicaudio you are loosing precision, with reencoding even more.

[MrTroy]

Originally Posted by scharfis_brain

Reencoding AC3 is nonsense if you want to make an HDTV AVI File, because why HD-Video and SD-Sound?

In that case you could also say: reencoding to XviD is nonsense, why convert a perfectly good TS to XviD?

Truth is, encoding to XviD is to save harddisk space, and if you're going to do that, you might as well give the audio a somewhat lower bitrate.

[Prysme]

Originally Posted by blubberbirne

I used this script

LoadPlugin("D:\DVDSoft\dgmpgdec\dgdecode.dll")
LoadPlugin("C:\Programme\AviSynth 2.5\plugins\TIVTC.dll")

MPEG2Source("file.d2v")
tfm().tdecimate()
Lanczos4Resize(1280,720,0,0,1920,1080)

Works perfect for me

I've try it, it works perfectly !! thank you, could you explain me what is doing tfm and tdecimate exactly ?

[mrkazador]

http://www.samek.neostrada.pl/hdtv/hdtv2xvid.htm
A little old but should get you started.

http://nwgat.net/
A better up to date guide using x264.

http://www.chade.org/HDTV/software/index.htm
A guide using Gordian Knot.

http://www.abhdtv.net/forum/showthread.php?t=114
Ts to wmv9.