Choppy iMovie Output

[acatalan]

Hi,
I have been having a few problems working with iMovie and my Camcorder files.
I have a Panasonic HDC-SD60S which gives me .mts files (h.264 video/ac3 audio, 1080i). VLC plays them without any problems but Quicktime does not, but this is something you would expect.
There are many video converters that do the MTS-->MP4 (i.e. Handbrake), so they can be imported by iMovie, but it takes time and you can always notice that the quality is not the same. A little while ago I found out that Quicktime can play h.264 and that mts was only the container, so I looked for software that could do that work. I found a couple that this was a much faster process (only needed to reencode the audio from ac3 to aac) and the quality was the same. I tried Remux, Smart Converter, BlueXFree, FFMpeg (commd line) among others. The result seemed to be awesome: same quality video and fast conversion. Quicktime is able to play the files with no problem and iMovie is able to import them and work with them.
Here is the problem:
- Once I have my project ready in iMovie and I share it (or export it) the result is a choppy video, no matter the output settings (I tried many).
- If I want to preview the project in iMovie without sharing or exporting it, it plays flawlessly.
- When I use converted videos (those with a bit less quality that take much longer to convert) the problem goes away and the shared/exported video is flawless.
- No matter the software I used to demux/mux the MTS into MP4, the result is always the same choppy scene.
- I can import directly from the camcorder to iMovie and avoid this, BUT, the files created are huge and it does not solve my problem with the files that are not longer in the camecorder memory.
- In bootcamp with Movie maker I can import the MTS directly and the result is flawless. But I HATE movie maker, I like iMovie a lot.

Any of you guys have any clue about what is going on? I would really like to keep using iMovie and not have to reencode my original video files. Thanks in advance.

-AC

[rumplestiltskin]

Please upload a sample of the "bad" video so we may see the problem and the specs of the video.

[acatalan]

Please upload a sample of the "bad" video so we may see the problem and the specs of the video.

Okay, here a zip file with the specs (text files) of:
1.- MTS original video
2.- MOV file remuxed with SmartConverter
3.- MP4 file remuxed with REMUX
4.- MP4 file converted (reencoded) with FREE MTS M2TS Converter

The video that iMovie outputs (M4V) showing the two choppy and one normal output. And the original MTS file.

Thanks for your response!

[jagabo]

Your source is normal 1080i30 video and the output is 30p at a lower resolution. My guess is imovie is having problems reading the source video because MTS is hard to seek accurately (the encoder may be requesting frames out of order, whereas playback in imovie is all in-order). Try converting the MTS to a low loss, all i frame, intermediate codec before futher editing.

[acatalan]

Your source is normal 1080i30 video and the output is 30p at a lower resolution. My guess is imovie is having problems reading the source video because MTS is hard to seek accurately (the encoder may be requesting frames out of order, whereas playback in imovie is all in-order). Try converting the MTS to a low loss, all i frame, intermediate codec before futher editing.

Hi, I am not sure I understand, but it make sense that when reading mts (or the same video in the mp4 container) it has problems. The original source has a framerate of 59.940 fps and the output has 29.970 fps. I am not an expert but there may be a problem.
If you noticed the last sample plays with no problem, and in that case the codec is the same (or almost the same, since it is reencoded) as the original source but this time at 29.970 fps.
So do you think that iMovie can't handle this mts files @ 59.940 fps?
Is there a workaround to it?

Below I have attached a screencapture showing the info of the MP4 files. On the right side the original (remuxed as MP4), and on the left the one that is converted to MP4 (this is the one that gives me the good output)

[jagabo]

Your MTS file isn't 60 frames per second. It's 30 frames per second, interlaced. Each frame contains two fields, intended to be viewed seaparately, and sequentially, at 60 fields per second. The combination of deinterlacing, out-of-order processing, and maybe a problem with your remux, is causing the problem.

Note that a nomenclature problem was created a few years ago by marketing gurus. One company started calling 30i video 60i (both are 30 frames per second, two fields per frame). Since one company started doing it all the others had to follow (or lose sales to what sounded twice as good). Then engineering was forced to change the file headers to indicate 60i instead of 30i so users wouldn't complain that such-and-such program reported their videos were 30i instead of the advertized 60i. So now there is much confusion on what these numbers mean. Both in the minds of the public and in software. Originally the number indicated the frame rate, the i/p indicated whether the frames were interlaced or progressive. 60i should mean 60 frames per second, interlaced, 120 fields per second. But it doesn't.

[poisondeathray]

The remux was probably using a ffmpeg based tool (they have problems with interlaced AVCHD transport streams, hence the error in frame rate)

Try can try clipwrap , there is a free trial

[acatalan]

The remux was probably using a ffmpeg based tool (they have problems with interlaced AVCHD transport streams, hence the error in frame rate)

Try can try clipwrap , there is a free trial

Hi there, I tried clipwrap, it does work, it "wraps" the video as a m4v or mov and its output from iMovie plays well. However, it takes a lot of time to to iMovie to import it. Around 5 minutes for a 50 seconds clip whereas any of the others take around 15 seconds, included the converted mp4.

Thanks jagabo for the explanation. I don't know what else to do, I have tried other "re-wrappers" like Wondershare video converter, RewrapAVCHD... same choppy results.

I am starting to give up, please comment if you have any other suggestion.

[Herve]

So do you think that iMovie can't handle this mts files @ 59.940 fps?

the concern with iMovie is not the input video, it's the output video (your input has 60 different pictures per second, but iMovie only keeps 30 after editing, during its export)

Is there a workaround to it?

change your editing software, to FCPX for example, or to the old and "not fun" iMovieHD/version6 (this version was "rough", had "no video gadget", so it only edits your videos while preserving their contents )

bye

[Herve]

However, it takes a lot of time to to iMovie to import it.

'cause iMovie converted your "rewrapped video" into its own editing format (aka AppleIntermediateCodec video format). This step is a conversion to an editing format, so time (and disk) consumming.
Just a question: why do you not import directly with iMovie? the result will be the same (1st iMovie rewraps -internally- your input stream, and then it converts it to its editing format. So exactly the same behavior…)

bye

Happy new year

[rumplestiltskin]

The problem is the 60fps. Example: Panasonic TM700 can shoot 1080 at 60fps but the result is both unplayable and uneditable on virtually all computers. It can only be played back from the camcorder to a TV. Why? The required codec hardware is only present in the camcorder, not in the computer. Workaround: Shoot 1080 at 30fps and the problem disappears.

[acatalan]

So do you think that iMovie can't handle this mts files @ 59.940 fps?

the concern with iMovie is not the input video, it's the output video (your input has 60 different pictures per second, but iMovie only keeps 30 after editing, during its export)

Is there a workaround to it?

change your editing software, to FCPX for example, or to the old and "not fun" iMovieHD/version6 (this version was "rough", had "no video gadget", so it only edits your videos while preserving their contents )

bye

Well, I am kind of new to Mac (a little over a year using it). I am not going to buy FCPX to do something I think iMovie should do (which is, to output a video without problems if the sources are imported and previewed without problems). Movie maker does it, although it does not have so many features as iMovie.

However, it takes a lot of time to to iMovie to import it.

'cause iMovie converted your "rewrapped video" into its own editing format (aka AppleIntermediateCodec video format). This step is a conversion to an editing format, so time (and disk) consumming.
Just a question: why do you not import directly with iMovie? the result will be the same (1st iMovie rewraps -internally- your input stream, and then it converts it to its editing format. So exactly the same behavior…)

bye

Happy new year

Okay, there is a problem then. Because iMovie imported many of my re-wapped videos (And by this I mean the same video processed with many applications) in a very short time. And iMovie also imported quickly my converted video (converted but using the same h.264 codec), and this is the one that gave me the good output but with a noticeable quality loss. So there was no need to convert all of these to AIC. All of this tells me that iMovie can work with h.264, the problem may be the framerate.

And answering your question. I don't want to import from the camcorder to iMovie because it does not solve my problem with the videos I already deleted from the camcorder memory (a lot, two years using it), and it takes a lot of space (4 to 5 times bigger per video).

The problem is the 60fps. Example: Panasonic TM700 can shoot 1080 at 60fps but the result is both unplayable and uneditable on virtually all computers. It can only be played back from the camcorder to a TV. Why? The required codec hardware is only present in the camcorder, not in the computer. Workaround: Shoot 1080 at 30fps and the problem disappears.

Unfortunately my Panasonic does not allow me to shoot at 30fps


Thanks a lot Herve and rumplestiltskin for your suggestions. For now I think I'll do the work (it is nothing fancy) with Movie maker, and when I need more features I'll use iMovie importing from the camcorder.

Thanks again!

[rumplestiltskin]

Edit: Deleted.

[Herve]

just a notice:

iMovie […import…] takes a lot of space (4 to 5 times bigger per video).

right, but it converts your movie to an "editing format" (far simplier to handle if you don't have the last hardware / a lot of processors )

I readed -a long time ago- somewhere… a iMovie's hack: (from memories) something to change in its plist and iMovie accepts to handle "double framerate".
No idea where I readed it, not tried at all (I do not use iMovie) so I don't even know if it worked.

bye

[Overcrancky]

You need to change ClipWrap defaults to produce an iMovie friendly container that can be ingested without transcoding: http://www.divergentmedia.com/blog/fullpost/clipwrap_248_imovie_secrets

Furthermore, I'd strongly recommend deinterlacing before importing into iMovie (e.g. via JES Deinterlacer or ffmbc).

[houdini2]

I have tried the ClipWrap secret. Did not work on my 50i AVCHD mts (from a Sony camcorder)... iMovie imports rewarp h264 mov as 25p AIC mov.

But Panasonic AVCCAM QuickTime component allows to open them directly in QuickTime Pro (or MPEG Streamclip) so as to export them in 50i AIC mov. 50i AIC mov are just copied by iMovie '11.

houdini

[Overcrancky]

I have tried the ClipWrap secret. Did not work on my 50i AVCHD mts (from a Sony camcorder)... iMovie imports rewarp h264 mov as 25p AIC mov.

But Panasonic AVCCAM QuickTime component allows to open them directly in QuickTime Pro (or MPEG Streamclip) so as to export them in 50i AIC mov. 50i AIC mov are just copied by iMovie '11.

houdini

If you are OK with AIC, you can transcode directly from ClipWrap.

[houdini2]

I have tried the ClipWrap secret. Did not work on my 50i AVCHD mts (from a Sony camcorder)... iMovie imports rewarp h264 mov as 25p AIC mov.

But Panasonic AVCCAM QuickTime component allows to open them directly in QuickTime Pro (or MPEG Streamclip) so as to export them in 50i AIC mov. 50i AIC mov are just copied by iMovie '11.

houdini

If you are OK with AIC, you can transcode directly from ClipWrap.

Nothing interesting just 50€ to waste.

houdini

[Overcrancky]

Many people would disagree. And QT Pro is not free if $ is a consideration.

[smrpix]

..