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MillimeterThe Cheap DVD Player and You
Jun 9, 2005 11:32 AM
For the DVD author outputting primarily to recordable media (DVD-R (+R), the cheap fifteen-dollar DVD player is more than a nuisance - it's a scourge.
Everywhere we look we find unsuspecting folks snapping up these "bargain" machines. Sure, the boxes are versatile: Most play PAL as well as NTSC titles; most are region-free - and almost all are subject to poor playback of DVD-R (+R) discs.
Out-of-sync playback is the hallmark of these el cheapo units; the poor performance being invariably attributed by most viewers to a defective disc.
Of course these folks after having invested all of $15 do not even consider the player itself could be the culprit. Back goes the disc to the store or vender, and the DVD author ultimately takes the heat.
In theory, of course, if a disc is authored and encoded to the DVD specification and the player is designed and manufactured to the same spec, all will be fine in the promised land of DVD playback.
But when player manufacturers cut corners as they are inclined to do, we DVD authors start to shake in our Amaray cases. After all, there's only so much we can do to ensure our DVD-R and DVD+R titles perform satisfactorily on the lowest of the low-end players.
Keep in mind that the player is not a computer, and that fundamentally the unthinking box simply has to decode a single multiplexed stream. It doesn't need to understand or know about Photoshop files, WAV, AIFF streams or the difference between DVCPRO and DVCAM. DVD players were designed from the outset to be stupid, reliable - and most of all, dirt cheap.
The stupid DVD player has implications for DVD-R (+R) playback compatibility. First, the DVD-Video format requires that the player give priority to the video portion of the multiplexed stream. Only after the video stream is decoded can the player begin decoding (if necessary) the audio.
If the player through poor design or sloppy manufacturer fails to decode the video in a timely fashion, the audio is allowed to slip back. There is no time-code or locked audio in DVD Land. The player decodes the audio and subpictures (menu overlays and subtitles) when it gets around to it, and in cheapo players struggling with the vagaries of recordable media as it is, this could be a while.
So why do DVD players have trouble playing back burned i.e. non-replicated media? Lots of reasons, and here's where things get a bit complex. My theory is that most DVD-R (+R) discs actually have a slight warp in them; this warp being more apparent towards the outside of the disc which explains why erratic playback occurs most often in higher number Tracks, Titles, and Video Title Sets.
DVD authors and producers outputting to DVD-R (+R) should therefore stick to only top-grade name-brand media. The bargain basement stuff with lots of warp is widely available for mere pennies per disc but keep in mind the wretched stuff has already been likely rejected by the major manufacturers.
This DVD-R compatibility business is hard enough without the added complication of substandard media.
Here are a few more tips to improve the playback reliability of DVD-R (+R) discs in all DVD players - not just the cheap ones:
- Burn discs slow - no higher than 2X Fast living and fast burning gets you to the finish line too soon. At 4X and 8X speeds, you're burning a deluge of unnecessary errors into the disc, errors which may not be fully correctable in players with poor correction circuitry.
- Encode video no higher than 7.5 Mbps maximum bit rate. Due to the lower reflectivity of recordable media, high encode bit rates over 7.5 Mbps may impede some players' ability to satisfactorily decode multiplexed audio and video streams in real time.
- Use Dolby Digital AC-3 - not PCM To facilitate playback of video at moderate to high bit-rates, the use of compressed audio, i.e. Dolby AC-3, is imperative to avoid player stutter or freezes. While AC-3 compression always entails some compromise in audio quality. the smaller file size and gain in player compatibility are usually worth it. Cheap DVD players often have trouble reading PCM audio from recordable media!
- Avoid burning to the outside edge of the DVD-R (+R) disc Compatibility problems increase as a player's laser tracks outward from the hub of the disc. Maintaining 5% - 10% of free space on a DVD-R (or DVD+R) may reduce read-errors in this vulnerable edge region where "warp" often becomes a factor.
- Consider replication instead of duplication
If you require more than fifty discs of a title, it may make more sense to replicate your DVD. A typical price for a minimum run in some markets is currently about $1000 - $1200 per thousand discs with a simple label and box. Replicated, i.e. pressed discs will always be significantly more compatible in more players than DVD-R (+R) media.
Regardless of authoring platform - I use Sonic Scenarist and Apple DVD Studio Pro - every DVD author faces the prospect of unreliable playback from DVD-R and DVD+R discs. This condition, already a factor in name-brand players, is exacerbated in the sub-par $15 boxes currently filling the market.
Not that we should eschew these cheap players completely. Bottom-end players can be useful for quality control by providing a reference to the lowest-common denominator.
One of these low-cost machines can offer invaluable insight into how your DVD-R (or DVD+R) will actually perform in the field. That's worth I'd say about $15 in itself.
Continue the discussion on “Crosstalk” the Millimeter Forum.
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