Any way from MKV back to DV?

[enonod]

I lost my presence of mind and converted DV tapes (720x576) to MKV to stream to TV via NAS. It worked but...
I did not retain the DV.

Is there any way back from MKV to the original 11Gb DV please?

[Baldrick]

You must reconvert to DV if you have changed video and audio codecs. You will lose some quality.

Use for example Xmedia Recode, load your mkv, under the tab Format choose profile: Custom and Format: AVI or DV, under the video tab choose Codec: DV and under the audio tab choose Codec: PCM. Select Destination folder, Add to queue and convert.

[enonod]

Thank you Baldrick. My understanding of formats and containers is, as should be clear, sketchy. I had the impression that MKV was 'simply' a container and that the video was not changed by my earlier conversion. I then assumed that I could change container and do the same in reverse with some software or other. I am obviously wrong and would be grateful for a brief word on what I actually did.

[manono]

I had the impression that MKV was 'simply' a container and that the video was not changed by my earlier conversion.

If you 'converted', then you did change the video codec. If all you did was change AVI to MKV containers, then the contents should still be the same. What's MediaInfo have to say about it?

[enonod]

I have done what I assume is correct to answer your question and attached a text file.
EDIT: The conversion following your instructions produced a dv at 4.38Gb for 21mins. I am not sure what MediaInfo is telling me and whether the size tells me I have the original DV. Perhaps a last word of advice from you would clear this up for me.
Thank you.

[Baldrick]

You have a mkv with MPEG2 video and AC3 audio and that is not DV so you must reconvert.

But do you really need DV/AVI-DV? You can change container to mpg or ts without reconverting.

[enonod]

You have a mkv with MPEG2 video and AC3 audio and that is not DV so you must reconvert.

But do you really need DV/AVI-DV? You can change container to mpg or ts without reconverting.

Actually I only started this because I am using Mac FinalCut Pro to edit and it does not recognise MKV but does DV. I was also concerned that the MKV being so small must have lost a lot of quality. So to get the best from my edits I hoped to go back to top quality and also have it recognised by FCP.

Final advice on the way to go for the best I can get would be very gratefully received.

[manono]

Final advice on the way to go for the best I can get would be very gratefully received.

The best you can get is what you have, which is very far from what you began with. If your program doesn't accept MKV, will it accept MPG or VOB? If so, extract the M2V video and AC3 audio and remux/reauthor. I have no idea how any of that is done using a Mac.

[enonod]

[QUOTE=manono;2411844]

If your program doesn't accept MKV, will it accept MPG or VOB? If so, extract the M2V video and AC3 audio and remux/reauthor. I have no idea how any of that is done using a Mac.

I believe MPG is OK. I will be converting using Windows. Do I use the same program you recommended (XMedia)?
My thanks for your continued assistance.

[manono]

Baldrick suggested XMedia Recode. One way to accomplish what you want is by using MKVCleaver to extract the M2V and AC3, followed by muxing into MPG using ImagoMPEG-Muxer.

[enonod]

Baldrick suggested XMedia Recode. One way to accomplish what you want is by using MKVCleaver to extract the M2V and AC3, followed by muxing into MPG using ImagoMPEG-Muxer.

Thank you both very much for your help, I will experiment and come back if I don't get anywhere.

[PuzZLeR]

I know you agree that retaining the DV video as your Source is your best option. If you've only just re-muxed to a different container like MKV, going back is simple to AVI.

Obviously, that wasn't the case.

Since you've not only remuxed, you've actually re-encoded the streams to a different format. IMO there is no point going back to DV at this point, and even increasing the file size for no benefit - unless you absolutely need DV (such as for further edits on FinalCut, or workflow, etc.), but I too wouldn't know how to do MKV->AVI, or even re-encode (back) to DV, on a Mac.

Since you've lost your original DV, and some quality from it - forever - then you may as well declare this MKV as your new Source, despite what you do afterwards. Or at least retain the streams if you wish to re-mux to MPG/VOB, depending on playback you're using. But retain the streams as your Source.

Baldrick's post in #6 says it all.

[enonod]

Thank you for your comments puzZLeR.

IMO there is no point going back to DV at this point, and even increasing the file size for no benefit

The one thing I could not understand was why I got Gb of DV (so called?) from Mb of MKV.
Did I get DV but of no better quality than the MKV?
I have not yet tried changing container to MPG to, as you say, make this my new permanent source, due to uncertainty on how.
Perhaps somebody could give brief instructions (for Windows).
Thank you.

[smrpix]

Are you using FCP7 or FCPX? It makes a huge difference. Make sure you have QT7 loaded on your Mac, not just the useless QTX. And be sure you have Perian loaded. With Perian installed you should be able to load your mkv into compressor or MpegStreamclip or QTPro and output an unmolested, unconverted .mpg from your mkv. You may even be able to drop your mkv into FCP7 directly.

[enonod]

Thank you for your useful added comments smrpix;
I am using FCPX 10.2.2, on Yosemite 10.10.x with QT 10.
I obviously need to check a few things; I am new to Mac; and your suggestions leave me feeling that I really have a great deal to learn here.
Compressor I have but have not got around to trying yet.
I have tried using MKV direct into FCPX but all such files are greyed out.
Perian meant nothing to me but I have now followed that up to see that it might permit MKV so progress may occur.

[smrpix]

FCPX will encode everything to ProRes anyway (that's why I asked) -- so you may want to use compressor coupled with Perian to beat it to the punch and avoid a double conversion.

[enonod]

Sorry to be dense but are you saying that if I obtain mpg from the mkv FCPX will not encode to ProRes422 thus one conversion OR convert mkv to ProRes422 thus one conversion... as opposed to, get mpg which 'will' then be converted anyway thus two conversions?

[smrpix]

Correct, FCPX will convert to ProRes. If you can not find a way to get it to accept your file, you can export to ProRes externally and ingest that so it doesn't convert twice.

[enonod]

Thanks for that smrpix. I now have a few hours of experimenting and hope I don't need to come back.

[poisondeathray]

Not sure if it still works, but SD MPEG2 can be imported into FCPX if you rename .mpg to .mod . That would save you the time for conversion (and minimal quality loss) to prores

For your MKV re-wrap to mpeg-ps (.mpg) , you can use an ffmpeg batch file in windows. Or there are ffmpeg GUI's that you can setup such as ffqueue to batch process . You should be able to do something similar in terminal on the mac as well

The windows batch file to rewrap (not re-encode) would look something like this

for %%a in ("*.mkv") do ffmpeg -i "%%a" -c:v copy -c:a copy -f vob "%%~na.mpg"
pause

[Cornucopia]

It'll (MPEG/MOD) convert to ProRes with FCPX. There's no way it can't, with AVFoundation-based apps (which is what FCPX and QT X is now).

Scott

[enonod]

Thank you for comments poisondeathray and Scott, I think I am having trouble knowing what type of conversion causes further loss and what doesn't.

smrpix said:
FCPX will encode everything to ProRes anyway (that's why I asked) -- so you may want to use compressor coupled with Perian to beat it to the punch and avoid a double conversion.

I have now tried Perian with Compressor and it does accept the .mkv however on selecting the ouput settings required as ProRes422 (not HQ) it goes busy for several hours such that I have to force close Compressor. I get the mouse arrow back every so often but as soon as I move the mouse Compressor goes busy again and I can do nothing. So at present I am unable to extract .mpg from .mkv or convert it to ProRes. My original mistake seems to have led me into the middle of a minefield. I seem to have lost my way and should try Baldrick's XMedia Recode but I am afraid that I may end up repeating my original mistake and re-encode instaed of change container.

Can anybody answer the following for me please.
1. When ingesting any media to FCPX I get .mov, then if I transcode in FCPX to high quality I get .mov, is that a wrapper for ProRes, if so how can one distinguish between the two other than the folder name and file size?
2. Doesn't transcoding normally increase loss?
3. If I use a video converter to change .mkv to ProRes should I presume I will lose more quality?

[enonod]

Update:
I have used MKVcleaver and extracted xxx.m2v and xxx.ac3.

1. Can somebody please tell me how to put them together again in a suitable container.
2. By doing this have I avoided any loss of quality so far?

Also I have converted MKV to MOV using QT with Perian but I don't know whether it converts/transcodes, how can I tell if I have lost quality and also whether the MOV is ProRes.

Any help please?

[smrpix]

When you open your new file in quicktime and go to the inspector (apple-I) it will show you the basic characteristics.

When you convert out of quicktime 7 there is always an options button to let you choose your output settings.

[Cornucopia]

Mov is THE wrapper for ProRes. In fact, prores doesn't (normally) exist outside of mov. Mov is the default QuickTime/AVFoundation container, whether the codec inside is prores, h264, dv, animation, etc.

You distinguish between files by using a reader/player/editor that accepts the formats. In this case, I'd recommend QuickTime player (7) or even better MediaInfo.

Unless transcoding to lossless formats (in QuickTime's case, e.g. Animation at 100%), transcoding is always losing quality. How much loss depends on the codec (prores loses very little).

As per the rule above, yes you will usually lose some quality Transcoding from mkv to mov.
You can tell by looking at the image and/or by doing an amplified differencing.

Scott

[enonod]

Thank you smrpix and Scott, I am a little wiser now. I shall plod on experimenting and see where I get. It seems I need to do some reading.

[enonod]

A little more help if possible please.
I have tried Brosoft converter and it has produced from MKV (mpeg2) 700MB a MOV (ProRes422) 50GB for a one hous-ish video and it took one hour to convert. It should then ingest directly to FCPX.
1. Is that what should be expected as normal.

I ask because...

PuzZLeR said in post #12:
IMO there is no point going back to DV at this point, and even increasing the file size for no benefit

Has this increased for no benefit despite having to go to proRes unless FCPX would have converted something else to a smaller ProRes?

[Edit]The ProRes shows as full HD but started as standard DV 720x576 then MPEG-2 unknown size. Does that mean it will be pixel doubled or something thus perceptually viewing poorer than correct size? Have I done something wrong?
Thank you.

[Cornucopia]

700MB / 1hr = 5600 Mb / 3600 sec = 1.5Mb/sec. Low for MPEG2, but unfortunately not that uncommon.
50GB / 1hr = ~111Mb/sec. On par with expected ProRes 422std (or LT) FHD data rates.

You must have done something wrong, or the converter (badly) may not be giving you the option. ProRes CAN be SD up through HD to UHD & 4k, even 5k resolutions, so it's not the codec's spec holding you back.

That bit about increasing the filesize vs. benefit is basically true, with an equivocation: if you've dropped the filesize (aka bitrate) already, it is now going to be at that quality (or less) regardless of any increase in the size/bitrate of the next generation. You may NEED to raise the bitrate to avoid losing any (or much) MORE quality, however. You may also need to raise the bitrate if the next generation's codec works only at such higher rates - this is the case with ProRes 422std level. Don't know if you could go down to the ProRes Proxy level and still retain the existing quality.

Scott

[enonod]

Thank you very much for coming back Cornucopia with that useful information. I doubt that it is the converter at fault, but certainly I am, it did have a Settings button but the numbers overwhelmed me and my scant knowledge (which is growing daily) did not permit me to change nit rates or anything else lest I completely screwed up (well I have now learnt that doing nothing also screws up).
Using the information you have provided and my available time, I shall now do some trials with various settings.

There is so much varied quality information on the internet on these subjects; are you able to point to a good article/site that would cover my shortcomings. Facts regarding what to strive for and what happens if one overcooks it would seem to be a better way to compare the resultant video quality than the eye.

[enonod]

A final query (I hope).
When I use the XMedia Recoder suggested by Baldrick I obtain the following information in MediaInfo for the starting MKV file and the resulting DV file.
The details of the M2V data extracted by MKVcleaver suggested by manono are of course the same as the MKV.
Taking all the subsequent information into account...

1. How did the resulting DV file have a much higher bit rate?
2. How was the pixel size restored from 352x288 to the original camera o/p of 720x576?
3. Why did the pixel size change to 352x288 in the first place, using MakeMKV?

If anybody can enlighten me or tell me why the questions are wrong I would be most grateful.