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AVI splitting problems: Sound does not sync up
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MaicoWin
Newbie
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30. October 2006 @ 20:11 |
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I am trying to split this .avi that I ripped from my DVD. I ripped the DVD (into some .vob files) using DVD Decrypter and compressed it into an XviD .avi file with AutoGK. The movie is about 16 minutes long and comes out to about 550MB (I wanted to retain the original quality, so that's why it's so big a file), but I only wanted to split it into a 4-minute segment so it shouldn't be that big a file in the end.
I've tried splitting the movie using VirtualDub, but when I save it the audio does not match up with the video. One of the warnings I got when I first tried to open the .avi was this
I then searched around and found some threads where people suggested using NanDub and VirtualDubMod, since those could handle the VBR audio, so I downloaded those and tried splitting it again, but it still wouldn't work.
Anyway, these test ones I did split by using the Full Processing mode instead of Direct Stream copy (because it said that mode couldn't do the VBR audio right) the file came out to about 7.7GB for all three of the different Dub programs, and the audio still doesn't match up right. I tried compressing the 7.7GB file using the XviD settings but the 4-minute segment file was now larger in size than the 16-minute original file, and the audio still didn't sync up right.
Is there a easy way to do this? All I want is my 4-minute clip of the movie. It's so complicated. Is there anything I can do with the .vob files to make it easier, maybe compressing the .vob into an .avi that doesn't have the VBR audio?
Update: I was playing around and got it to work finally. What I did was re-encoded the .vob file with AutoGK but changed one of the audio settings so that the audio would be a CBR instead of variable, and the file came out to about the same size as the file when I encoded it using the VBR audio setting, so that's good.
But one thing that is bugging me is that when I split the file using VirtualDub (XviD compressions) the 4-minute segment is roughly 300MB which is half of the 600MB 16-minute clip. Shouldn't the split file be 1/4 size at 150MB, since it is 1/4 of the video? The only thing I changed in the XviD configuration is the quantizer to 1.0.
Is there any way I can compress it further without losing significant video quality? It looks pretty much like the original file it was split from, so that's good. I guess I'll have to encode all the DVDs I rip into CBR audio instead of VBR if I want to split it up, since I don't know how else to split it and make the audio sync with VBR audio.
This message has been edited since posting. Last time this message was edited on 30. October 2006 @ 21:06
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aldaco12
AfterDawn Addict
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3. November 2006 @ 04:39 |
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Read my FAQ. You have to uncompress that VBR audio and use an audio stream made with that WAV instead of an audio stream made with that VBR MP3.
What I do whan I make DVD --> AVI is to prepare a MP3 CBR or AC3 stream, first (with HeadAC3he for the MP3 or FFMPEG GUI for the AC3).
Later, when I make the AVI I use VirtualDubMod for the video loading my audio stream with its command Stream___Strem List --> Add.
Otherwise, you can use VirtualDubMod to replace the VBR audio with a new CBR one (Do: Stream___Sttream List ; Disable the VBR one first then Add the CBR one you made wit either HeadAC3he or FFMPEG GUI).
You'll just to have some caution when you create a MP3 CBR with HeadAC3he (press [options>>] couple of times after choosing MP3 as final format).
Creating AC3 is easier (AC3 is only CBR), but not every PC has an AC3 codec (like AC3Filter) installed [and not every application encodes AC3 sound], so having an AVI with AC3 audio is less useful than having an AVI with MP3 CBR audio.
If you have an AVI wit AC3 audio you have to Demux the AC3 stream, convert the video part only of the AVI into a MPV, then authoring the DVD starting with those 'elementary streams' (see my 'sticky' post: MPV + AC3 [with IFOEdit] = DVD files (VOBs made by multiplexing video + audio) = full DVD)
This message has been edited since posting. Last time this message was edited on 3. November 2006 @ 04:44
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MaicoWin
Newbie
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5. November 2006 @ 11:55 |
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Thanks for the guide, Aldaco.
I'm not sure if I'm making the output .mp3 into 128 CBR though. Here's a screenshot of what my HeadAC3he program looks like before I hit the start button. When I compare the demuxed .mp3 to the one that HeadAC3he outputted, I can distinctly hear the lower quality of the output .mp3, it's not as crisp or clear as the original. What setting do I need to change in HeadAC3he to make it a higher quality bit rate .mp3?
And when I interweave the new audio stream into the video file, does it change the size of the video drastically? If it doesn't affect the file size, should I just encode the new audio at 320 CBR?
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aldaco12
AfterDawn Addict
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5. November 2006 @ 22:58 |
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Perfect. You'rer exactly at the right point.
You now just have to set some options in the LAME Configuration screen.
For a 'normal' movie, you have a good sound quality simpy by choosing the LAME Preset: Alt CBR. If you do so, HeadAC3he will create a MP3 CBR 128 kbps.
If you want to prepare a different bitrate MP3 you have to make some little efforts.
Please note: the size so LINEAR with the bitrate (and it is seen in VirtualDub's bitrate calculator) , so:
- a MP3 192 kbps sound is 1.5 * MP3 128 kbps sound. The size should be calculated by HeadAC3he, bit remember that 128 kbps (128/8) = 15 Kb/s = 900 Kb/min = 52,7 Mb/hrs (1 MB = 1024 kb).
A good 'rule of thumb' is:
- for normal movies, 96-128 kbps is more than acceptable (music needs high bitrate, speech needs lower bitrate);
- for movies where music is impornat (lime musicals like Nicole Kidman's "Moulin Rouge" or DVDs of concerts) 160 is the minimom accptable bitrare. 192 kbps is optimal (1+1 channels).
- the best sound is AC3 (Dolby Surround, DVD quality), but it's noticed only if you have surround speakers. Its bitrate can be either 384 or 448 kbps, depending on the DVD, but have a fixed delay (which can be removed only extracting the stream with ReJig in IFO Mode (opening the VOB IFO file it will tell you even the name and the bitrate of the available streams, sould you have more than one stream) but, since AC3 have a fixed A/V delay, you have to check the box 'correct AC3 delay').
But, since surround speakers are not so common, AVI with AC3 sound are almost never found. AC3 sound (provided the AVI goes to one which owns surround speakers) might be useful when you compress 1h movies (or 2h movies split in two files: movie_CD1.AVI and movie_CD2.AVI) with lot of songs, like Disney's movies (and you'll notice the difference between MP3 192 kbps only if you have surround speakers).
The procedure to compress MP3 CBR with HeadAC3he is a little complicated, and is this one:
1) select the WAV and set output formay to MP3
2) press the [options >>] button, until you reach the Lame configuration screen
3) set AVE to your destired bitrate (K)
4) set MIN to K
5) set MAX to K (4 and 5 can be inverted, in order)
6) choose Preset: NONE (very important)
7) set Mode: CBR (very important)
The only problem with HeadAC3he is that if you have a WAV extracted from an AVI instead from a DVD it often stops signaling some error message.
In this case, it's better to use FFMPEG GUI. It is more user friendly, but it lets you only encode DVD streams: MP2 (not accepted by AVIs) or AC3 (fine, but you need an AC3 filter instaklled, to listen to AC3 sound on your PC ).
FFMPEG GUI is able to prepare AC3 (48000 Hz is the DVD standard) 128 to 448 kbps. Obviously, if you start by a 1+1 ch WAV stream you won't be able to prepare a 5+1 AC3 stream (garbage in = garbage out), so I use it only to prepare DVDs from AVIs and I use FFMPEG GUI to prepare 128, 160 or 192 kbps AC3 streams. 224 or more is a waste of room, which is better to save for the video.
Good work!!
This message has been edited since posting. Last time this message was edited on 5. November 2006 @ 22:58
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