• transcode can't handle VBR/ABR* MP3, only CBR^*. If you really need VBR MP3 audio then you'll have to stick with MEncoder. Note that the AVI tools that come with transcode won't work with AVIs that contain VBR MP3 audio. Therefore you cannot fix synchronization problems in MEncoder generated AVIs with the avisync utility.
• There's no nice GUI for MEncoder at the moment. This makes cropping/resizing rather painful.

• 4:3 movies that fill the whole picture (no letterboxing*): scale 5:4 to 4:3
• 16:9 movies that fill the whole picture (again no letterboxing): scale 5:4 to 16:9
• 16:9 movies that are letterboxed: scale 5:4 to 4:3 and cut away some of the black bars
• 2.35 movies that are letterboxed: scale 5:4 to 16:9 and cut away some of the black bars

If you want to understand what is really happening then you just have to do some math. Let's assume that the DVD is encoded with 720x576 which is 5:4, and its flags indicate that it should be played back at 16:9. This means that the player has to change the picture's aspect ratio from 5:4 to 16:9 by either scaling to 1024x576 or to 720x405. How to I calculate these values? Well I simply multiply the width with (display AR / encoded AR) which is (16:9 / 5:4) = 1.78 / 1.25 = 1.42. It's similar for the latter case. But this includes the black bars that may be present! So if your DVD cover says that the movie has an aspect ratio of 2.35 then you still see black bars on this scaled picture.

4.2. Using dvd::rip

After starting dvd::rip you rip the titles you wish to transcode to your hard disk. Refer to chapter 3 for a detailed description.

4.2.1. Clipping and zooming

transcode uses three steps to bring the picture to its final size: first it clips the unscaled image, then it does resizing and last it clips again. Each of this steps can be left out by selecting 0 for clipping and the original width and height for resizing. Each window shows the result of those three steps. If you want to see how big the pictures really are then just click onto any of them and a pop-up window will be opened containing the result.

You may have noticed the drop-down listbox below the three preview windows. dvd::rip offers a wide rage of presets for you to work with. Simply select one of those gives you a place to start. You can still change the values manually after selecting such a preset. All presets that are named "autoadjust..." try to guess the correct clipping regions. After selecting a preset hit the Apply Preset Values button. Now adjust the values you got until you're happy.

The big frame, medium frame and small frame parts refer to the final image size that is to be achieved. big keeps almost full DVD resolution, medium is somewhere between 500 to 600 for the width and small is somewhere around 350.

Do you remember that I asked you to check if the video was interlaced? Now we need it. If your video is not interlaced then simply leave deinterlacing to and antialias off. Otherwise select 3 - Zoom To Full Frame. This is the slowest but best looking deinterlacer. Again here's the interlaced sample from Ally McBeal. You can see the result from 3 - Zoom To Full Frame in the first deinterlaced picture.

Another filter for deinterlacing is provided by an external plugin (don't worry you've already installed it with transcode itself). Have a look at the lower right. There's a input box labeled transcode options. All options entered here are simply passed along to transcode. We can use this for deinterlacing. Here's the same picture as above deinterlaced with other deinterlacer. This deinterlacer is faster than the 3 - Zoom To Full Frame option. If you want to use this deinterlacer then set deinterlace to off and enter -J dilyuvmmx in the input line.

dvd::rip tries to autodetect your framerate. If it failed you can correct it here. Use YUV internal should always be yes unless the output codec does not support YUV modes. XviD does. Leaving it on gives a huge speed boost. DivX multipass should be yes as well unless you only want to do a preview. For final results always chose two pass encoding. Although this is labeled DivX multipass it works nicely with XviD as well.

The audio options should be self explanatory. You chose either to reencode the audio to MP3 using the specified bitrate or to use the original AC3 sound without reencoding. AC3 audio provides surround sound and all those advantages but is bigger than MP3 sound. It's really your choice. If you use MP3 then make sure that the MP3 Quality setting is at 2. According to lame's documentation (lame is used for MP3 compression) higher quality settings like 1 or 0 - best but slower are at lot slower but do not produce significantly higher quality. The volume rescale allows normalization the audio which does not require a separate (external) program. dvd::rip automagically scans the sound and provides a rescale value.

In the upper right is the bitrate option. You can easily chose the rip size by selecting the count and size of CDs you want to use. Manipulating the Target Size or the Video Bitrate works as well. dvd::rip automatically updates the calculated values below so finding the optimal bitrate is rather easy.

4.2.3. Generating a quick preview

When you're done click Transcode. After a couple of minutes at most your AVI/MPEG will be ready. Now have a look at it (like mplayer my-new-file.avi). This is a good moment to see if deinterlacing works as expected and to check if audio and video perfectly synchronized. If they are, you're set. If they aren't, then read on:

4.2.4. Preventing audio/video desynchronization

Now is really a fine time for some socialising :-)

4.2.6. For advanced users: transcode command line arguments

As a last note you will find that transcode as of version 0.6.0pre6-20020529 contains support for libavcodec via a still experimental export module written by me. You can activate it by using -y ffmpeg4 (remember: libavcodec is part of ffmpeg) instead of your previous codec. dvd::rip does not support it at the moment (read: it is not in the list of selectable codecs).

4.3. Using MEncoder

• -oac copy - MEncoder needs the audio information from the first pass in order to keep audio/video synchronization. You mustn't use -nosound, although I suggested it in earlier versions of this guide. If you want the technical details then have a look at the MPlayer mailing list.
• -o /dev/null - The output of the first pass isn't needed either, so just dump it.
• -ovc lavc - chose lavc as the Output Video Codec.
• -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vqmin=2:vqmax=31:vpass=1 - libavcodec actually supports a handful of different video codecs. With vcodec=mpeg4 we chose the MPEG4 compliant encoder. vbitrate=1000 is the desired bitrate. vhq (very high quality) tells the encoder to spend a lot of time optimizing the results. It is worth it. vpass=1 finally tells the encoder that this is the first pass only. Using vqmin and vqmax tells the codec how much it may compress the video at least and at most. Keeping these at their defaults (see man mencoder) restricts the achievable output bitrate a lot so I advice choosing a broader range. Note that I'm no expert on quantizers. If I'm wrong here please drop me a line.
• -vop scale=640:480 - scale the picture down to 640 by 480 pixels. I've read on the mailing list that a new switch has been added that automatically calculates the height from the width or the other way round so that the aspect ratio will be kept. I haven't tried it myself but it should look like this: -vop scale -xy 640 . Note that while it is possible to actually enlarge the picture I strongly advise against it. There are several drawbacks: the encoder needs a lot more bits to achieve the same quality you'd get when encoding a smaller picture and then scaling it up while playing it back, and you might even get distorted pictures (Peter Schuller reported such a case to me). Always scale down.
• If your picture is interlaced you can deinterlace it with -npp lb.
• We only want a preview so we provide the start position and the length: -ss 0:20 specifies 20seconds into the movie as our beginning, and -endpos 0:30 says that we want 30seconds to be processed. This parameter is named badly as it's not the end position but the duration that it specifies.

Here's the command line:
nice -+19 mencoder -oac copy -o ally-preview.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop scale=640:480 -npp lb -ss 0:20 -endpos 0:30 /space/first.vob
After MEncoder finishes take a look at your preview. Adjust parameters if needed. Redo the preview until you're happy with it.

4.3.4. Generating the final AVI (both passes)