By Werner Ruotsalainen on Mon, 04/30/2012
UPDATE (08/20/2012): THIS post directly compares the remuxing speed of iVI and the, more or less (if you can live with the nagging screen upon loading a file and the disabled batch processing) free MP4tools. Very similar results to mine (read: iVI should NOT be used for MKV remuxing).
UPDATE (08/03/2012): HERE, I've elaborated on how iVI joins MP4 (MOV / M4V) videos without (!!) transcoding them; that is, very quickly.
Just drag the first video in the app, then, double-click it in the list, select the Video Joining tab (fourth) and drag the additional, to-be-joined videos there in the order you want to join them.
If the videos are in the same format + resolution + fps, they will be joined. This means this app is, highly recommended for MP4 joining as well - in addition to MTS remuxing.
Forum members asked me for my opinion on iVI (Pro) by South Pole Software, which is also a video converter with simple remuxing capabilities. That is, it doesn't necessarily re-encode the entire video if it already contains H.264 video compatible with the hardware H.264 decoder of iDevices. Then, as has already been explained in several of my past, video-related articles, you save about 90-95% of the conversion time (video recompression is always a very time-consuming process). In addition, the quality of the video doesn't decrease (consumer-level recompression is lossy; therefore, it results in degraded quality).
In the Apple Mac AppStore there are hugely different opinions on the app: a lot of people love it, and the others hate but there didn't seem to be an objective benchmark and comparison of the converter there and noone has really published a really all-in-one benchmark-review of it. This is also contributed to my desire to dedicate quite a few hours to properly evaluate it. I've tested both versions: iVI Pro (pro version with DVD ripping, only available on the developer's homepage) and the AppStore version without DVD ripping ($4, as opposed to the $10 of the non-AppStore Pro version. The latter doesn't have a Lite version; the former has a trial.)
First and foremost, I do NOT recommend it for MKV conversion or generic recompression purposes (you'll soon see why). For camera / Blue-ray hi-res (M(2))TS conversion (see THIS article for more info), on the other hand, it's highly recommended. Actually, it saves you a LOT of money – so far, I've preferred the $40 ClipWrap 2 for this. Now, you can get the same functionality for one-tenth the price – quite a steal, if you ask me!
Let's start with the GUI. You WILL need to change it in order to let it export full HD content (by default, it'll only output videos with 720p resolution but not higher) and pass-through (that is, non-reencoded simple remuxing). As it's, IMHO, not very beginner-friendly, I explain what you'll need to change in order to use it as a(n at least for MTS remuxing) highly useful app.
Upon the first startup, you'll see the following:
You must uncheck the fourth item (Apple TV 2 / iPad 1/2 / iPhone 4) and, while you're at it, also uncheck the second, iTunes item:
Now, we'll enable remuxing (here it's referred to as “Pass-through”). Go to the third tab (“Conversion”). It'll look like this:
Check the “Enable Pass Thru Conversion” checkbox (the one in the bottom right). Do NOT touch the subtitle radio buttons (the red oval on the left), at least not yet!
Now, you're ready (click the Close button). Just start dropping your files onto the app and, after making sure the target resolutions are right, click “Convert all”.
For Full HD MTS files, target resolutions were all right. If you give it a non-standard video size (for example, 960*540 WMV's 720*576 PAL DVB TS videos, 1024*768 videos produced by the Canon IXUS SD950 camera etc.), it'll want to convert them. For example, the following shot shows my 960*540 WMV test video – the app wants to upsize it to HD resolution, as can be seen in the “HD” label in the third, "Format" column:
With videos like these, you will still want to prefer the free and much faster Handbrake, though.
(Incidentally, instead of “NO”, you'll see “YES” for MTS videos that can be, instead of recompressed, directly remuxed in the next, “Pass Thru” column. The column will only be visible if you do allow for pass-thru mode (see the explanation for the “Conversions” tab above).
Now that you know how to set up the app for full HD remuxing (instead of recompressing, which noone wants with H.264 source videos), let's see its performance and compliance. Let's start with the one (and, I'd state, only) area I highly recommend the app for: H.264 camera (M)TS remuxing.
The MTS remuxing capabilities and compatibility of the app are, as has already been stated, excellent! Given that the app only costs $4, it's probably the best solution for (full) HD MTS remuxing. Just don't forget to disable any subtitle track adding if you do enable them for some reason (I wouldn't, not even for MKV's). If you forget it on, it reencodes the video track (with mencoder-burn), absolutely unnecessarily.
Now, let's turn to the question of MKV's (see my previous, dedicated article HERE), where the situation is MUCH worse.
First and foremost, conversion takes ages (again, I've tested this with both the AppStore and the Web versions). If you don't enable subtitles, it'll take about eight-nine(!) times longer than with avidemux or Subler, the two best solutions for MKV > M4V remuxing (dedicated article HERE).
If you enable subtitles, the app becomes even slower. For example, with a 21 Gbyte 1080p MKV having 26 ASS subtitles, the demuxing of the subtitles ALONE took 140 minutes on my test 2.8 GHz C2D 8 Gbyte/1TB 17” MBP. (Needless to say, no other apps ran on the desktop so that the results are reliable and comparable to the other ones.) A directory list shot showing this (taken from the temp directory of the app):
(Check out the timestamp of the first (12:58) and the last (15:17) ASS file!)
With iMkvExtractor (to extract all the subtitles from the same MKV file on exactly the same test hardware to be later added with Subler to the subtitle-less, by avidemux remuxed M4V), the same process took about 6 minutes – 23 times less! (Subler couldn't open the test MKV file directly so I don't list its total remuxing time here.) Basically, it took the app to spend about five minutes to extract each subtitle track. This is plain unacceptable if you plan to preserve subtitles.
(Nevertheless, if you, for some reason, still want to use this app to preserve subtitles, if you only enable it to extract only your language in the Settings, it'll finish much faster. It'll extract all the occurrences of the same language; for example, if the MKV has two English track, one of them forced – think of Avatar - , it'll extract both.)
On top of this, not only the subtitle extraction is painfully slow compared to iMkvExtractor (let alone the even faster Subler when used alone to do the full MKV > M4V remuxing), the video / audio conversion / remuxing is, as has been stated, 8-9 times slower.
Adding insult to the injury, the app uses at least three times temporary storage of the original, source MKV size as, after extracting the ASS / SRT etc. subs, it creates a subtitle-less MKV of the same video (filewithoutsubtitles.mkv; 13 minutes to create from the 21 Gbyte test MKV), then, it extracts the AC3 audio track (audio0.ac3) and creates two additional tracks (also taking some 16 minutes for the creation of the 200 Mbyte audio0ff.mp4!); then, creates an audio-less video track (Moviename.m4v, taking 10 minutes), starts creating the video etc. If this wasn't enough, it doesn't display any error message before the conversion telling the user he doesn't have the necessary free space. It's quite a bit annoying to get an operating system error message after 2.5 hours of converting a 20+ Gbyte MKV that the app crashed...
Needless to say, decent and free(!!) MKV > M4V remuxers like Subler or avidemux do not require any additional temporary storage (apart from the target file's size) and, as has already been stated, are much-much faster.
All in all, I wouldn't bother - it's just not ready for the prime time, at least when it comes to MKV conversion. While it may run significantly faster on SSD hard disks – but so would the recommended remuxers like Subler or avidemux.
Other file formats (recompression tests & benchmarks)
Canon XGA 15 fps AVI: OK
SD PAL MPEG2 DVB streams (TS):
- doesn't handle subtitle OCR in any way (dedicated article HERE); therefore, no subs in the target file
- doesn't handle dynamic screen ratio changes at all: the second part with 4:3 of the dynamic change test will always use 16:9
- multiple audio tracks are OK
With the high-resolution test WMV, I've directly compared the time needed for recompression with the app to that of the most popular, free re-encoder tool, Handbrake. The latter needed 1:22 (everything default (1-pass)) / 2:26 (2-pass without turbo first pass) for the conversion; iVI 3:08, that is, way more. That is, Handbrake is not only free but also much-much faster, even using its highest quality mode. (iVI used the default “Normal” quality, see the group in the upper right corner of the “Conversion” tab in Settings.)
All in all, I do NOT recommend the app for re-encoding either (unlike for MTS remuxing). Use Handbrake for that instead.