Converting 23.976fps Divx to 25fps SVCD..

[drewid]

hi,

i have been trying to convert a divx to svcd with tmpgenc 12j. I rip the audio from the divx using virtual dub, and also convert the video to 25fps and save it seperately. I open cooledit and shorten the audio so that it matches the new length of the 25fps divx. After tmpgenc encodes the svcd i still find the audio is creeping out and by the end it still is about 1/2 - 1 second out of sync. Can someone please help me as i am starting to go bald because of this :/ or can someone point out if i am doing anything wrong.. thanks in advance...

Drewid

[drewid]

could it also be something with the divx audio rate being 48k and the svcd being 44.1k ?? or should 48k on svcd not be a problem??

[JJamez]

As long as you're using 'Convert Sample Type' and NOT 'Adjust Sample Rate' in CoolEdit to adjust the rate to 44.1k, that should not be a problem.

I think whats happening is this - the time length you are using (length of the 25fps video) is slightly off.

Try using this method on Nicky Page's site - it involves using a program called AVI Info which you can d/l there. Read the whole article, but specifically what you are looking for is about halfway down the page under the heading:

'To apply it or not to apply it, that is the question?'

Basically it allows you to get a very exact figure (a percentage actually) that you will input into CoolEdit, which should fix your problem.

Here's the link - http://www.digital-digest.com/nickyguides/audio-synch.htm

[drewid]

thanks alot, i will give it a try and post my results!!

just one question.. my divx is 23.976 fps.. do i save it as a 25fps video stream and just leave the audio stream?? can you give me step by step instructions please!!

<font size=-1>[ This Message was edited by: drewid on 2001-10-01 18:46:12 ]</font>

[JJamez]

Just set the frame rate conversion and Save as avi.

This will obviously leave you with an out of synch avi, but then just follow the guide at the link I posted - again, the part that applies is about halfway down the page under 'To apply it or not to apply it, that is the question?' but its well worth reading the whole guide. Following the guide, you'll eventually stretch the audio to fit the video length and remix the 25 fps video with the newly stretched (and hopefully synched) audio.

Ya know, you can also do all of this right within TMPG - just load the original divx avi as the video and audio source, set the output frame rate to 25, change the audio output to 44.1 (if you want), and TMPG should take care of the rest while keeping everything in synch. The problem with this method is on some conversions I seem to get jerky video (it seems as if TMPG is skipping frames to keep synch), but this doesn't happen every time, and I'm not sure why - sometimes it looks fine. You can give that a shot too, although I imagine the other way is better, though its more complicated.

[drewid]

i think i might be having a problem with avi info as when it plays the audio and video simutaneously it slows the fps probably t olike 10fps and audio remains at 25fps :/

[drewid]

it seems that when i use virtual dub to convert the video something has gone foul. I load my divx, CRTL-R and choose change to 25 frames per second. I set video/audio to direct stream copy and then save as avi... when its done i get the before mentioned 10fps or so video with standard audio.. im using version 1.4.7 of virtualdub by the way..

[drewid]

ok what ive worked out is that if your audio and video source are the same, then all you need to do to get your
percantage for cool edit is divide your wanted frame rate by the source frame rate eg. 25/23.976 .. and thats it.. worked like a charm for me.. thanks for all your help!!!

[snowmoon]

Drewid,

You are doing it the hard way, AVIsynth has a built in frame rate speedup/slowdown function that resamples that audio too. Just feed the .avs to TMPGenc and encode.

Cheers

################################################## #####
# Copyright 2001 Eric Warnke
# Free for non-commercial use, please give credit
################################################## #####
#
# Generic .avi to VCD, and SVCD conversion
# script. Allows converion between PAL->NTSC
# frame rates. Please use AVISynth 1.0b3, as not all
# functions work under 0.3
#
# Follow directions and uncomment lines where necessary
# when done you should have a complete conversion sctipt.
# For simplicity I assume..
# VCD = 352x240/288 with a frmae rate of 23.976,29.97/25
# SVCD = 480x480/576 @ 23.976,29.97/25
#
# I do not answer simple questions at above email address
# but I will take any corrections/alterations.
#
################################################## ######
#
# Load video source
#
# Uncomment ONE of the following lines to load
# your source. Make sure to include the full path to
# your avi source or this may not work.
#
#1 Use for most normal .avi files including Divx
#AVIFileSource("moviename.avi")
#2 Use next line only for LARGE .avi's
#OpenDMLSource("moviename.avi")
#3 Use Next line only for virtualdub/avi_io segmented .avi's
#SegmentedAVISource("moviebase.avi")
#4 Use for odd formats that play though MP see AVIsynth doc
# for more info. Can open MS DV files.
#DirectShowSource("movie.mpg")
#4a if you notice off colored lines when using Directshowsource
# use the following line
#FixBrokenChromaUpsampling()
#
################################################## #######
#
# Load external audio source ( if necessary )
#
# This will overlay an .wav file over the movie. Great for use
# with program like DVD2AVI that produce a seperate .wav file.
#
#1 If necessary load external .wav file for movie
#audioDub ( WAVSource("Mymovieaudio.wav") )
#2 bump audio if necessary -in seconds-
#delayaudio(1)
#
################################################## ########
#
# Video size / bordering
#
# Use one of the following to get a properly resized borderd
# video based on input and output. All resize values have
# been rounded to the nearest 16 to prevent macroblock waste.
#
# NOTE: These are only applicable to PROGRESSIVE material
# do not attempt to use these for interlaced material as
# you will end up with a big mess.
#
# If you input is -- 4:3 -- and you are going to ....
# NTSC and a format of
#1 VCD
#bicubicresize(352,240)
#2 SVCD
#bicubicresize(480,480)
# PAL and a format of
#3 VCD
#bicubicresize(352,28
#4 SVCD
#bicubicresize(480,576)
#
# If you input is -- 16:9 -- and you are going to ....
# NTSC and a format of
#5 VCD
#bicubicresize(352,176).addborders(0,32,0,32)
#6 SVCD
#bicubicresize(480,352).addborders(0,64,0,64)
# PAL and a format of
#7 VCD
#bicubicresize(352,20.addborders(0,40,0,40)
#8 SVCD
#bicubicresize(480,432).addborders(0,72,0,72)
#
# If you input is -- 2.35:1 -- and you are going to ....
# NTSC and a format of
#9 VCD
#bicubicresize(352,144).addborders(0,48,0,4
#10 SVCD
#bicubicresize(480,272).addborders(0,104,0,104)
# PAL and a format of
#11 VCD
#bicubicresize(352,160).addborders(0,64,0,64)
#12 SVCD
#bicubicresize(480,320).addborders(0,128,0,12
#
################################################## ########
#
# Misc functions
#
#1 Clean up head noise or other garbage at top and bottom
# of the video frame by adding black borders VCD only
#letterbox(8,
#2 Clean up head noise SVCD
#letterbox(16,16)
#3 If you get a technicolor mess as your mpeg output, this option
# may be necessary. If you have YUY2 or huffyuv as source and
# going to CCE you will probably need this option.
#ConvertToRGB()
#4 PC -> TV brightness correction
#levels(0,1,255,16,239)
#5 Audio rate correction. If your audio is not already 44,100
# many encoders will complain, use this to correct
#resampleaudio(44100)
#6 Fix for broken codecs that decompress upside-down
#FlipVertical()
#
################################################## #######
#
# Frame rate converion ( if necessary )
#
# Uncomment one of the assumefps or change fps lines if
# frame rate conversion is necessary. If you video is
# already in one of the three following 23,976,25,29,97
# and not chaning it's format you do not need to use
# one of the following lines.
#
# First three add and drop frames, last two speed/slow
# video and audio to proper FPS ( 1.0b3 only ) it's a
# better method, but is only applicable to two specific
# conversion senarios.
#
#1 Irregualr FPS converison to NTSC film rate
# use this for 10,15,20 -> NTSC film conversion
#ChangeFPS(23.976)
#2 Irregualr FPS -> NTSC frame rate
# use for 10,15,20 -> NTSC conversion
#ChangeFPS(29.76)
#3 Irregular FPS to PAL frame rate
#ChangeFPS(25)
#4 NTSC film 23.976 -> PAL 25
#assumeFPS(25,sync_audio=true)
#5 PAL 25 -> NTSC film 23.976
#assumeFPS(23.976,sync_audio=true)
#
#
# Thats all folks, assuming you have everything installed properly
# You can now open this file in TMPGenc, CCE, MP, and most other video
# applications.
#
# END OF SCRIPT