Forum Archive Home -> Video Conversion -> Question: 29.97fps IVTC to 23.97 and Audio
Question: 29.97fps IVTC to 23.97 and Audio | ||
| Quigonsean posted 2003 May 05 12:04 | ||
| Hey all,
I got a question here. I've been doing the Star Wars Trillogy. I cap directly in mpeg2 at 720x480:29.97fpf NTSC. Now my questions are if I convert this down to 23.97fps (My capping proggie De-Interlaces as it captures) and then run Pulldown, or encode directly with the 2:3 flag do I have to do anything with the audio to keep it synced. I am encoding with CCE 2.66. Or as opposed to Demuxing then running through a transcoder to goto 23.97 and all should I if using cce just go ahead and keep the file muxed and demux for authoring after the encode? Now to convert in the first place I create a d2v file in dvd2avi and then use vfapi to get an avs to use in cce or to use with Avisynth to cce. If I wanna goto 23.97, should I set dvd2avi to "ForcedFILM" I did notice if I do, it seems cce set to 23.97 encodes fine (I used a small test file) Or should I turn off forced film in dvd2avi so it stays 29.97, then set cce to 23.97. I would assume however it is done I do tick "Auto Detect 3:2" in cce. My main concern is audio. I tried like 6 differant ways all demuxed though so I was doing vid only. Each resulted in audio being abou 15-20 seconds behind. Oh I did not run Pulldown on any of these attempts, I set CCE to Auto Detect 2:3. Bitrateveiwer shows it at 23.97fps, but I figured that it should show in Bitrate Veiwer as 23.97, and cce would put the needed flag in with it set on auto detect 2:3. Am I wrong about that? Any help is greatly appriciated, Sean | ||
| adam posted 2003 May 05 20:39 | ||
| You cannot just convert to 23.976fps, you have to do an inverse telecine. Is this what you mean when you say your software "deinterlaces?" Depending on how the signal was broadcast, it might not even be possible to perform an inverse telecine. You may be forced to keep your captures at 29.97fps.
Forced film is only applicable to DVDs. If your source is 23.976fps then CCE should appropriately add the pulldown flags to your film, but some versions have bugs in this area. I'd use pulldown.exe for this instead. Finally, when film is telecined to 29.97fps, or vice versa, the audio is not changed at all. To increase the fps new frames are created from existing fields, so even there are more frames per second, but the number of seconds stays the same so therefore it still syncs with the audio. I think your audio problems are caused because you are not properly performing an inverse telecine. What software are you using to capture and what option are you using to inverse telecine (convert 29.97fps to 23.976fps)? | ||
| Quigonsean posted 2003 May 05 21:55 | ||
| Well I cap with WinDVR. It deinterlaces it, its still 29.97 but no longer interlaced, that is it combines the 2 feilds to make 1 frame instead of leaving it 2 feilds per second. As for IVTC I'v not tried yet. I was told that even though the vhs is 29.97fps the original film was filmed at 23.97, so it can and should be IVTC'ed. I didn't really use anything I happened to demux with DVD2AVI to get a d2v to load into vfapi for use with avisynth. Evertime I try usinf "DirectshowSource" etc... it never loadws so I run it through these 2 proggies to be able to use avisynth(I use AvsGenie to generate my scrips) It just happens I forgot to turn off Forced Film and when I looked in bitrate veiwer it showed 23.97, so I tried encoding with CCE in 23.97. I figured this was wrong thats why I asked. It's not really important to do it, I was just under the impression that it would help the quality, plus it makes it 20% smaller so I could increse the bitrate. I get alot of this stuff, but IVTC I seem to have a problem with.
Sean | ||
| adam posted 2003 May 05 22:10 | ||
| If you want to inverse telecine then you must not deinterlace. Set it to cap at 29.97fps interlaced and then run an inverse telecine filter. Since you are already using avisynth, this can easily be done. Download decomb.dll and read the help file to determine the syntax to use. Then add the IVTC command to your avisynth script.
Yes, performing an IVTC and bringing the framerate back down to 23.976fps has many benefits. Overall, quality will be better. You cannot use forced film for anything other than NTSC DVD. Most NTSC DVDs store the film at 23.976fps but include a pulldown flag which instructs the dvd player to telecine it in real time to 29.97fps. Forced film simply ignores this flag and exports the footage as it is stored, at 23.976fps. If you were to load an mpeg2 file that was actually encoded at 29.97fps, as opposed to one encoded at 23.976fps w/ pulldown flags, then dvd2avi would simply decimate random frames to decrease the framerate. If this is how you processed your footage than this is the cause of your sync problems. | ||
| Quigonsean posted 2003 May 06 15:46 | ||
| Cool thank you so much Adam, I get it now. I really appriciate your taking the time to help me out.
Thank You, Sean Ward | ||
| DruidCtba posted 2009 Oct 08 18:19 | ||
| Hi my friend ADAM, I have one AC3 audio extract from DVD NTSC 29.970 fps (interlaced, 2 h 10 minutes, 448 kbps) and one AVI with 23.976 fps (scan progressive, 2 h 33 minutes) and I don't get it synchronizes AC3 audio extract with AVI 23.976 fps :( .
I try stretched audio in Soundforge 10, Besweet (have problems with picth here the sound stay slowdown), I try Hypercube Time Streched 1.0 and nothing, it synchronizes in one point but any second's late it out synchronizes :cry: . Can you help me please, I need synchronizes this AVI with this one AUDIO, please :) ? I thank its aid antecipamente. Druid®. | ||
| manono posted 2009 Oct 08 21:07 | ||
| This thread is 6 years old. It sounds to me as if you have 2 different versions of the film, perhaps the theatrical and director's cut. In any event, for movies, given the same NTSC version, the length will be the same, whether 29.97fps or 23.976fps. Stretching the audio to try and fit it is the wrong approach when the longer version probably has extra scenes. What movie is this, by the way? | ||
| DruidCtba posted 2009 Oct 09 13:09 | ||
| Ok my friend manono, one friend in USA send me one compress avi HDDVD version from Terminator 2 Judgement Day DirCut 1991 AC3 audio English and I buy Terminator 2 Judgement Day in Brasil (because the imagem is hungly) I decid put the AUDIO PT-BR in this one HDRip but time duration is diferent in this ONE, HDVD is 2h 33m and my normal DVD is 2h 10m.
So I used Bsweet (29.970 to 23.976) and time from audio goes to 2h 43m (I don't understand...). Information: HDRip (Media Info) Vídeo Formato : MPEG-4 Visual Perfil do Formato : Streaming Video@L1 Conf do Formato, BVOP : Sim Conf do Formato, QPel : Não Conf do Formato, GMC : 0 warppoint Conf do Formato, Matriz : Padrão ID do Codec : XVID ID do Codec/Dica : XviD Duração : 2h 33mn Taxa de bits : 2 222 Kbps Largura : 720 pixel(s) Altura : 304 pixel(s) Proporção da imagem : 2.35 Taxa de quadros : 23,976 fps Resolução : 24 bits Colorimetria : 4:2:0 Tipo de Scan : Progressivo Bits/(Pixels*Quadros) : 0.423 Tamanho da Faixa : 2,38 GiB (83%) Biblioteca : XviD 1.2.1 (UTC 2008-12-04) Áudio Formato : AC-3 Formato/Informações : Audio Coding 3 ID do Codec : 2000 Duração : 2h 33mn Modo da taxa de bits : Constante Taxa de bits : 448 Kbps Nº de canais : 6 canal/canais Posições dos canais : Front: L C R, Surround: L R, LFE Taxa de amostragem : 48,0 KHz Tamanho da Faixa : 491 MiB (17%) Interleave_Duration/String : 42 ms (1.00 video frames) Interleave_Preload/String : 500 ms Thank you for any help, Druid® | ||
| manono posted 2009 Oct 09 19:37 | ||
http://www.thedigitalbits.com/reviews/t2ultimate.html Did you not understand what I wrote in my last post? You have 2 completely different versions of the film. The longer one contains scenes not found in the shorter version. What you want to do is impossible. |
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