m4v to MP4 ??

[The.King]

Hi folks,

I've searched the forum, but couldn't find anything specific on this. Hopefully someone can help?

I was given a copy of a friends wedding but it's in the .m4v container. I read somewhere that .m4v and mp4 are more or less the same thing and that some people even suggested to just change the file extension etc. (which doesn't work.) I get that they're more or less the same thing, but whilst my TivX media player has no issues in playing a host of containers .mkv, mp4. mt2s as well as all the normal .avi, wmv, mpeg2, .vob. etc. etc. - it will not for the life of me - play .m4v? (even with the latest firmware update.)

I've played with a lot of converters in my time (Handbreak & Staxrip to name but two - which I found easier than most to use as I prefer a front end program - like a one-stop-shop) rather than the more complex MeGUI or AVIsynth type-things that will give better encoding and reproduction - but also break my heart in the process.

Can anyone tell me the most straightforward program or option I could use to turn this .m4v file into .mp4 or .mkv without losing too much quality (or keeping identical quality is possible) and keeping everything else the same - i.e. pixels, sound (not going out of sync) etc.?

Would appreciate your views and if you could point me in the right direction? Maybe there's an easier way to do it without having to re-encode the file at all?

Thanks in advance.

[bat999]

Hi
Yamb will do the job without re-encoding.
"Yamb-2.1.0.0 beta2 with installer".
From here:- http://yamb.unite-video.com/index.html

[netmask56]

If you post a MediaInfo log of the file it would make it far more easier to come up with a solution and why it's happening. It might be the bit rate or resolution of the original file is not supported by your TivX media player. Normally you can just rename the suffix. That's what I do with my Beyonwiz PVR/media player for mv4

[The.King]

Hi
Yamb will do the job without re-encoding.
"Yamb-2.1.0.0 beta2 with installer".
From here:- http://yamb.unite-video.com/index.html

Sweeet! Cheers Bat999, just tried Yamb - it worked a treat. I could even remove unnecessary audio files during the process to make the file smaller.

Thanks for that.

All I need now, is to find out how to correct the audio sync problem (which was about a second out from the original source file and so now the new mp4 file is the same). If anyway has an easy way of doing this - I'd be very grateful.

Thanks.

[poisondeathray]

If the lengths of audio & video are the same, and it's only an offset (ie. the amount of desync is 1sec all the way through, it doesn't get progressively worse or better) , then you can enter a media delay in yamb . This will shift audio relative to video. (Click on the properties button)

[The.King]

Thanks poisondeathray,

Yep, from what I can tell, it seems to be the same amount out of sync the whole way through. Audio & video are the same length too.

Is there anything simple I can use to determine the length of media delay required? I'd rather not be guessing the whole time to try and get the sync just right as I could be here all night.

Thanks.

[poisondeathray]

most media players can shift audio on the fly in 10ms increments/decrements. The usual keys are + and - . So play the video and make adjustments, when it's in sync, make a note of the ms delay . e.g. it might be -500ms or +500ms depending on the direction . Enter that value in yamb

Some programs express it as a "delay" some as a "shift" . The direction is opposite. So you may have to play with the +/- to get it the right direction

[The.King]

Cheers for that, will give it a go and see what happens.

[Cornucopia]

FYI, @The.King, "m4v" is an elementary stream, aka it is raw - not in any container. That's the difference: mp4 is the container that m4v and m4a get muxed into to work together (that's what Yamb did).

Scott

[poisondeathray]

Nice grave bump Scott!

Depending on the application producing it, m4v can be either elementary stream or a modified mp4 container. e.g. "m4v" is an elementary stream for Adobe, but for Handbrake "m4v" a MP4 container . Historically, it's because of quicktime and the old MP4 specs which did not allow for AC3 audio. Although AC3 audio is part of the MP4 specs officially now, legacy quicktime can only handle it as m4v

[anana]

FYI, @The.King, "m4v" is an elementary stream, aka it is raw - not in any container. That's the difference: mp4 is the container that m4v and m4a get muxed into to work together (that's what Yamb did).

Scott

m4v can be a raw video, it also can be a container for video & audio
m4v support ac3
I know, coz i have it

see
http://superuser.com/questions/549179/using-ffmpeg-to-add-subtitles-to-a-m4v-video-file

[Baldrick]

Nice grave bump Scott!

It was a spammer the grave bumped it (now banned and removed).

[Cornucopia]

@pdr & @anna, ".m4v" IS officially only an elementary stream. Sure, you can co-opt it for some other proprietary use, but that only works in a closed system. Heck, I can say that ".MyD*ck" is a video container! Rename away.
But if you "look under the hood", for example with MediaInfo, it'll lay it out in plain sight as what it truly is. And if it is a "container for audio+video", it is going to say it is "MP4". I'd be money.

Scott

[poisondeathray]

Officially, it is also a modified MP4 container, developed by Apple. It is a registered ftyp type
http://www.ftyps.com/

You can "officially" blame Apple for this

[Cornucopia]

Well, you won't see ME using it like that!

Historically: M + # + A or V was reserved for elementary streams with mpeg. M1V=MPEG1 video, M2V=MPEG2 video...

Leave it to Apple to go against the grain and then expect everyone to follow their "lead".



Scott

(it is still mp4 under the hood, though)

[poisondeathray]

Yes, the m4v variant distributed from itunes store, or used in handbrake, is still basically a MP4 container. That's actually the more common file that you will find in the wild, so it's important to distinguish that it might be either/or container or elementary stream

Apple has always gone against the grain, but with their market cap these days , they are more influential than ever. They don't just appeal to artsy types anymore - they have big mainstream appeal to brainwashed "sheep"

(as I type this out my iphone... j/k )