What’s Important
Goals:
- No loss in quality from VHS to DVD
- No loss in quality from VHS to file format
- File format must be playable by Picasa on Windows
- Compatible with iMove and iDVD on iMac
- US and UK playability
I don’t care about:
- File size is not a concern, but quality is
VHS
VHS is a video tape that uses magnetic tape to store data. Data is written in analog encoding, NOT digital as a DVD.
Can play in VCR with an adapter. Content can be recorded in different speeds. With the different speeds comes a difference in quality.
Popular NTSC Resolution: 350 x 480 (250 lines)
There are two common length of tapes. They are T-120 and T-180. The number is the number of minutes it will play at SP (full quality)
Here are the typical play speeds
Values are in the format (SP / LP / EP). EP is also SLP
T-120 (120 min/ 240 min / 360 min)
T180 (180 min / 360 min / 540 min)
VHS-C
Same as VHS, but shorter tape.
Here are the typical play speeds
- SP – Standard Play – 40 minutes
- LP – Long Play -
- EP – Extended Play – 120 minutes (aka SLP or Super Long Play)
References
DVD
Frame size and frame rate
DVD’s in the US use one of the following formats:
- MPEG-2 compression at up to 9.8 Mbits/s
- 720 x 480 pixels at 29.97 frames/s, interlaced or progressive
- 704 x 480 pixels at 29.97 frames/s, interlaced or progressive
- 352 x 480 pixels at 29.97 frames/s, interlaced or progressive
- MPEG-1 compression at up to 1.856 Mbits/s
- 352 x 288 pixels at 25 frames/s, progressive only
- 352 x 240 pixels at 29.97 frames/s, progressive only
All resolutions support 4:3 frame aspect ration. Only full D1 resolutions support widescreen (16:9) video. MPEG-2 also supports progressive.
Audio
Audio on a DVD can be PCM, DTS, MP2, AC-3 (Dolby Digital). PCM takes a lot of space on a DVD that could be used for high quality video. Dolby digital has great compression and is supported by most fairly recent DVD players now. DTS may or may not be supported. PCM is not well supported.
Container
DVDs use a VOB container format. VOB contain Video, audio, and subtitle streams all multiplexed. The vidoe stream is MPEG, but must be at the specifications noted above and here. So, all VOB files are MPEG, but not all MPEG are VOB files.
References:
iMovie
Native formats:
- DV (Ditial Video) like from a camcorder
- DV Widescreen
- HDV 1080i (25 and 30 fps)
- HDV 720p (25 and 30 fps)
- MPEG 4 Simple Profile
- iSight
NOTE: MPEG-2 which DVD’s use is not shown. This just means we can’t take a video from a DVD and put it in iMovie. It does NOT mean that we cannot use iDVD to convert and burn a DVD from what iMovie EXPORTS.
Export formats:
iMovie can export to virtually any format with most any setting. The number of choices and options can actually be a bit overwhelming.
The one that I found to be the played the best on Mac and PC is what iMovie exports very easily and without much thought. Just go to the iMovie. Go to the Share menu and choose Export Movie… Select Large. From a resolution standpoint Medium should be sufficient for VHS, but I think Large is safer. Depends on your hard drive and amount of video as to which one you choose. Large is saved with a .m4v extension and uses H.264 for compression at 30 frames/s which is 4mbps.
Archive Format
I chose DV (digital video) because that is what it is captured in when I use FireWire. I believe the format that it is saved in is DV/DV PRO, but that should be verified. DV is a lossy compression. It is NOT lossless contrary to popular belief. It is an advanced codec that does a very good job of keeping quality and still give a good amount of compression. The DV files are still quite large, but I think it is worth it to archive videos with. I think it is overkill to just view, etc.
References
iMovie: Using footage from DV and non-DV sources
Analog to Digital Converter
If you are converting from a VHS or VHS-C tape, there are a few ways to convert them to digital. There is NO way to do this without a analog to digital convert. The converter does NOT have to be a stand alone converter, but it is 100% required to exist in the process somewhere. A converter can be a camcorder with firewire connection. These have analog to digital converters built in. In can be a VHS to DVD dubbing machine. It could be my choice, the Canopus ADVC300 Advanced Digital Video Converter. With an around $400 price tag, this can be expensive for small projects. I have over 85 VHS or VHS-C tapes so this is good investment for me.
My theory is that if I spend that kind of money on any of those devices, I want all the money to go to the analog to digital converter, not the lense on a camcorder, a dvd writer, etc. I believe this is the most important part of the process because if this is done poorly, there is nothing you can do to recover.
Be sure that the converter can sync audio and video even on long recordings. This is very important. The ADV300 noted above does this.
References
Using analog/Firewire convert devices with iMovie
VCR / Camcorder
If you have the camcorder or vcr that a tape was recorded on I highly recommend using that device as the player for the tape. The reason is that in many cases, a tape will never play as well in another devices as it does in the one that records it. I have read this on the internet, and been told that by a couple professional conversion shops. In fact, often professional shops have several decks to try to find the best playback quality of a tape. If you have the original device, you have the best already.
If you don’t have the original vcr, you may consider a new one and clean in between tapes. At the very least clean you existing VCR before you start the batch of tapes. The reason is that I think this is another critical place in the process. If the heads that you are using to read the tape are dirty there is no amount of hardware or software that fix the problem. Well, you can try, but you will create side effects.
It is best to get a 4 head and wi-fi sound.
Tips
How to Convert VHS to DVD – excellent tips!
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