I was trying to burn a video file to DVD today–not authoring a DVD, just putting the mp4 file on the DVD. This is something I’ve done before successfully.
However, the mp4 wouldn’t play properly from the DVD when I checked it. It would begin playing, but the audio quickly drifted out of sync and the video stopped and started and jumped. This was the case for three different media players (QT, VLC, and MPEG Streamclip).
The original file on the computer played fine on all three media players.
I tried converting the mp4 to a MOV with the same results–fine on the computer, playback problems from the DVD.
This is a 2010 Mac running Yosemite.
Any ideas what could be causing this? Could the DVD burner be messed up? A friend suggested that DVD+R is a wonky format and that DVD-R is better, but I’ve burned mp4/mov files to a +R before without playback issues.
The slow head movement of the DVD may cause the play back to skip packets.
the player believes it is playing over a network or from a badly scratched dvd and just plays whatever it has , if it can’t get what it wants.
It will stay out of sync till it gets a sync block that causes it to say "forget anything extra, play this video and that audio, starting “now”!
The mpg4 may have been encoded with out sync blocks required, which is fine if there is no dropped frames but its seeminly coming off that DVD too slow and dropping frames.
maybe its a slow DVD ? they code the speed into the DVD… “play me at X times” ?
If you copy the mp4 (or mov) file from the DVD back to the computer’s disk (being careful not to overwrite your original file) and then try to play the file from your computer’s disk (not the DVD), does it play properly?
The Video and the Audio are two separate streams in the mp4 file.
Your DVD player might not be able to sync “stitch” both streams correctly together from the DVD.
Just naming the extension as “mp4” doesn’t say what codecis being used for the video and/or the Audio stream and your DVD player has issues with that.
What also can happen, that the streams are located in different locations on the DVD and the DVD drive can not read it out fast enough (relocate the laser).
Just to confirm: You’re copying an existing, working, mp4 file to DVD, not creating an mp4 file from another file and writing it to DVD in the process? If so, use a binary file comparison tool to compare the two files. (I can’t really recommend one for Mac; there doesn’t seem to be a readily available built-in one. Perhaps someone else will have a suggestion, but there seem to be plenty of free and commercial options.) If there are no differences, the problem isn’t directly media related. If there are, then you’re failing to burn the DVD file properly for some reason – software error, failing burner, something.
I can’t really recommend a file comparison tool for Mac. There doesn’t seem to be a readily available built-in one. Perhaps someone else will have a suggestion, but a quick google shows plenty of free and commercial options.
If there are no differences, it may be that your DVD player isn’t able to supply your video player with content from the video and audio streams fast enough, and that the player is compensating for this in ways you don’t like. You can go a long way to confirming this by copying the file from the DVD back to the disk, and playing it from there, as Alley Dweller suggests. Does it work now? If so, by far the most likely explanation is that the DVD drive is just too slow to support playback of your file.
Yeah, this was my first thought as an Obvious Thing To Try.
Thanks for the ideas, all. I did copy the files from the DVD back to the computer, both mp4 and mov, and they played fine.
I just tried popping a bunch of pre-recorded DVDs into the player–some played, some not. I’m thinking the problem is with the DVD unit, definitely with playback and possibly with burning too. The fact that some movies play fine, some badly and some not at all suggest some kind of idiosyncratic problem. I’ll look into replacing the drive.
I’m not a Mac guy, but the main problem is DVD±R (recordable DVDs) are simply notoriously unreliable as a storage medium for very large files. When you ‘author’ a DVD±R video you are conforming to a very specific standard, in fact the standard that DVD discs were made for in the first place (i.e. movies). When you merely ‘copy’ files onto them you’re using the DVD data disc standard, which is a combination of computer and DVD standards. Combine this with burnable discs (which are inherently less reliable than factory ‘pressed’ ones) and a very large, all-one-chunk file structure (as with a large .mp4 file) and you’re going to get a lot of unreadable discs.
Optical media like burnable DVDs are nearly reaching obsolescence in the computer storage world. Besides being unreliable their read/write speeds are incredibly slow when compared to even platter hard drives (let alone solid state memory & thumb drives)…