H.264 to mpeg2 - very slow
by Raven Plenty
on
Sep 25, 2008 at 1:35:40 pm
I have two different H.264 quicktime movies that vary widely in their processing times to convert to MPEG-2 using compressor (DVD Best Quality 4:3).
Source 1 - 20-minute video (NTSC source, 29.97 fps), 640x480, 2000 kb/s - about 8 hours conversion time (video only, no audio)
Source 2 - 2-minute video (animation, 30 fps), 1280x1024, 4700 kb/s - about 6 minutes conversion time (video only)
Extrapolating the 2 minute video to a 20 minute video puts it up to about 1 hour conversion time. I would have thought it would take longer to convert the 1280x1024 video. Any insights into why there's such a huge difference in conversion times?
Re: H.264 to mpeg2 - very slow by Rafael Amador on Sep 25, 2008 at 1:58:45 pm
Hi Raven,
I think that once converted to H264 the original format (Animation or DV) it doesn't matter.
But is really strange the difference. Should be the opposite timing.
H264 is a slow to compress codec, but I thin is really fast to de-compress.
Unless you have different setting in the Compressor's "Frame control" I can't understand such big difference.
You may try to export the H264-DV to an uncompress format (8b Unc) or Proress, them make the MPG2.
Rafael
Re: H.264 to mpeg2 - very slow by Raven Plenty on Sep 25, 2008 at 2:06:28 pm
The other difference is that the 20-minute video was created by Handbrake (as an H.264 mp4 file, which I resaved as MOV) whereas the 2-minute video was created from a Combustion animation. But H.264 is H.264, no?
Re: H.264 to mpeg2 - very slow by Chris Poisson on Sep 25, 2008 at 3:13:54 pm
H264 is NOT an editing codec, and files from Handbrake are useless, no wait, worse than useless, in FCP. That is nowhere near a professional app, files from it have to be uprezed to a codec you can edit, but will look horrible.
Re: H.264 to mpeg2 - very slow by Raven Plenty on Sep 25, 2008 at 3:25:26 pm
I'm not using Final Cut, nor am I doing any editting. Only transcoding using Compressor.
I'm not making the case for Handbrake as a professional worktool, it was a last ditch effort to create a backup copy of a single copy-protected DVD we were going to use for a convention. Nor am I intending to use H.264 files in an editing workflow.
All that aside, are you suggesting that the H.264 file was taking extra long to transcode to mpeg-2 because it was created by Handbrake?
Re: H.264 to mpeg2 - very slow by walter biscardi on Sep 25, 2008 at 3:34:08 pm
[Raven Plenty]"All that aside, are you suggesting that the H.264 file was taking extra long to transcode to mpeg-2 because it was created by Handbrake?"
Anything that has been compressed once and is being re-compressed takes longer than working with a native editing format. So taking H.264 and converting it to MPEG-2 takes much longer than if you had an 8bit Uncompressed video file and converted that to MPEG-2. That's been our experience.
Walter Biscardi, Jr.
Biscardi Creative Media HD and SD Production for Broadcast and Independent Productions.
Re: H.264 to mpeg2 - very slow by Raven Plenty on Sep 25, 2008 at 3:49:00 pm
I have a feeling that this thread isn't being read from the beginning.
I realize that it takes longer to transcode from one compressed format to another. However, this H.264 file is taking way longer than a different (and much higher res) H.264 file to transcode to MPEG-2. Please review my earlier postings for more details.
Re: H.264 to mpeg2 - very slow by Chris Poisson on Sep 25, 2008 at 4:20:33 pm
Compressor is the same as FCP as far as how it handles QT files. What Walter said should explain the slowness to you, very clear. My point was that H264 is a delivery codec, highly compressed, not something to start with for further compression.
I went back and read your original post, what you need to do is start over and get your material in an editable format.
Re: H.264 to mpeg2 - very slow by Daniel Low on Sep 25, 2008 at 10:25:02 pm
Huh?
Raven, I agree, those responding to this thread either haven't read it properly, or haven't understood your question.
Guys: Raven wants to know why one H.264 clip takes longer to compress than another H.264 clip.
Chris, why should she need to "start over and get your material in an editable format", H.264 is not only a delivery format H.264 is capable of 10bit 4:4:4 at 4K to over 950Mb/s - andto wide spread acquisition formats like AVCHD
P.s. I noticed that the FishEyeEdit clip on your home page is neither 1.33:1 or 1.78:1 (it's 1.48:1) and uses a frame size that's not very suitable for Flash (which loves dimensions divisible by 16 on both axis). Lovely content though.
__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!
Re: H.264 to mpeg2 - very slow by Rafael Amador on Sep 26, 2008 at 1:37:28 am
[Daniel Low]" H.264 is capable of 10bit 4:4:4 at 4K to over 950Mb/s - andto wide spread acquisition formats like AVCHD " But I think you need special software to compress with those HQ profiles.
MPG-2 is capable of 422 but you can not make a .m2v 422 with Compressor.
Rafael
Re: H.264 to mpeg2 - very slow by Zane Barker on Sep 26, 2008 at 5:32:05 am
[Daniel Low]"Guys: Raven wants to know why one H.264 clip takes longer to compress than another H.264 clip. "
I now quote my last post on this thread.
[Zane Barker]"Not ALL h264 files are compressed equally. One of your files probably has a much higher amount of compassion thus taking it much longer to convert to something else. "
There are no "technical solutions" to your "artistic problems".
Don't let technology get in the way of your creativity!
Re: H.264 to mpeg2 - very slow by Rafael Amador on Sep 26, 2008 at 6:48:02 am
Hi Zane,
Normally acquisition formats are really fast to encode although some of them can take a certain time to decompress.
Delivery formats can take long to compress but they must be able to be decompress in RT.
rafael
Re: H.264 to mpeg2 - very slow by Daniel Low on Sep 27, 2008 at 1:20:41 pm
Compassion has nothing to do with it ;-)
Nor does higher compression.
What I think you might be referring to is GOP structure, reference frame distance, number of b-frames and the like.
__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!
Re: H.264 to mpeg2 - very slow by Zane Barker on Sep 25, 2008 at 4:23:16 pm
[Raven Plenty]"this H.264 file is taking way longer than a different (and much higher res) H.264 file to transcode to MPEG-2"
Not ALL h264 files are compressed equally. One of your files probably has a much higher amount of compassion thus taking it much longer to convert to something else.
[Raven Plenty]"Please review my earlier postings for more details. "
I believe people are reading them, the reason they are confused is because you posted this question on a Final Cut Pro Forum, a forum where questions about the use of FCP are asked, so it is assumed unless you state otherwise that you are going to be using that video with FCP. You never told anyone that until later.
Your post probably belongs in the Compression techniques forum.
There are no "technical solutions" to your "artistic problems".
Don't let technology get in the way of your creativity!
Re: H.264 to mpeg2 - very slow by Raven Plenty on Sep 25, 2008 at 4:30:49 pm
Thank you very much Zane. I did not notice that there was a forum for "Compression techniques" – I looked for Apple Compressor, and since I didn't see that went with what I thought was the next best. I'll repost there since I'm still interested in more information about this (i.e. if there is anything unusual happening or if this is normal).
Re: H.264 to mpeg2 - very slow by Rafael Amador on Sep 26, 2008 at 12:57:51 am
Hi Raven,
The truth is that, at least my self, need to learn more about H264.
MPG2 is around since 20 years, and the compression system and GOP structure is quite easy to understand.
H264 uses more complex compression techniques. So time to look for a document where everything is clearly explain. Any suggestion.
What I agree is that you should have started ripping the DVD to a high quality editable .mov. DV50, 8b Unc or even Prores.
Go MPG2>h264>MPG2 I don't think is a good workflow.
Cheers,
rafael
Re: H.264 to mpeg2 - very slow by Raven Plenty on Sep 26, 2008 at 3:17:16 pm
It's been pointed out to me numerous times that I should not have gone from m2v to H.264 to m2v (which is unrelated to my original question, but I do appreciate the comments.) The problem was that the source DVD was copy-protected so my options were limited. (I wanted to simply extract the pertinent m2v file and burn a backup from that.) I had to use what I had at the moment (Handbrake, which only does H.264 and mpeg-4 I believe) since I didn't have much time to look for other options.
So what are methods to rip a copy-protected DVD to a high quality .mov? (Bearing in mind this was strictly to create a backup copy for use at a conference – just in case the original when missing, snapped in two, etc.)
Let me know if I should start this as a new topic in a different forum.
Re: H.264 to mpeg2 - very slow by Chris Poisson on Sep 26, 2008 at 11:45:39 pm
Raven,
Well, two things, if the material on the disc was truly a copyright violation to copy, then you're stuck. If not, there are other methods to get around encryption besides Handbrake. (Odd, that name congers up scenes of Emergency!, which is another name for that thing in cars.)
When you capture from a disc player through a deck to some NLEs or third party capture software, encryption is sometimes not detected. Remember though, if it is protected, you stand liable for violations.
I don't remember seeing this mentioned in your thread, but have you tried MpegStreamclip to export from the VOB files on the disk? Don't know if it will see the encryption or not, worth a try as it's free.
Re: H.264 to mpeg2 - very slow by Rafael Amador on Sep 27, 2008 at 1:41:17 am
Hi Raven,
If you have the right to copy the DVD, you can use MacTheRipper (http://www.mactheripper.org/).
If you don't have the right you know you can't do it.
Extract the VOBs. Then with MPGStreamClip, convert the MPG2 to QT.mov.
Export at least as DV50 to get the most of the picture.
Never export as DV.
Rafael
