with the new Canon Camcorders offering the option of recording AVCHD or MP4, which are the pros and cons of one over the other?

They are both AVC h.264 compression, so the image quality should be the same. I prefer mp4 because I can keep the native mp4 files in events folder in iMovie and use them as they are, no need to convert to AIC, proRes etc.

The image quality is relative the same, but AVCHD is the video format with specification (you can't go over 28Mbps etc) while mp4 is free type of files (it can go over 28Mbps).

Have both types in one camera is fain.

It seems that LPCM audio is only available with AVCHD.

Ron Evans

Looks like you don't actually need to make a choice over which one to record in, you can record in both.
From Canon USA website:

Full HD 1920x1080 Recording Capabilities
Multiple recording modes, resolutions and frame rates make the XA25 Professional Camcorder creatively flexible and adaptable to virtually any production environment. It can record in Full HD resolution in both MP4 and AVCHD Progressive recording codecs, at multiple bit rates, and even simultaneously.

So while I can't offer any guidance as to which would be better to record to, looks like you can see which looks best, & what runs best through your editor then make a decision!

These new Canon cams certainly look interesting!
Regards,
Bryce

They are both AVC h.264 compression, so the image quality should be the same.

This is certainly NOT true, logically or in fact. The AVC h.264 compression comes in lots of variants - these include whether lossless CABAC encoding is used, the number of reference frames, the bitrate etc. Even within the different 'profiles' (baseline, main, etc.) there are variants. For example, on one Panasonic camera, the AVCHD at 60p uses 28Mbps, and 'high profile' and CABAC. The 30p MP4 uses 'main profile' and no CABAC at 20Mbps. It is not obvious which is better, but they sure are different.

I would choose MP4 at 35 Mbps, especially if you're on a Mac. AVCHD only goes up to 28 Mbps.

Recording Bitrates - Canon XA20/25 and G30 from Canon website
AVCHD:
28 Mbps, 24 Mbps, 17 Mbps, 5 Mbps
MP4:
35 Mbps, 24 Mbps, 17 Mbps, 4 Mbps, 3 Mbps

It seems that LPCM audio is only available with AVCHD.From the specs it looks like LPCM audio is recorded to both AVCHD and MP4. But the 5.1ch feature is only supported by AVCHD/28Mbps (at 23.98??).

Audio Recording system
Linear PCM (2ch)* / Dolby Digital (5.1ch when SM-V1 is used) * Feature supported only in the 28 Mbps/23.98 Mbps recording mode; resolution: 16 bits

I would choose MP4 at 35 Mbps, especially if you're on a Mac. AVCHD only goes up to 28 Mbps.

Recording Bitrates - Canon XA20/25 and G30 from Canon website
AVCHD:
28 Mbps, 24 Mbps, 17 Mbps, 5 Mbps
MP4:
35 Mbps, 24 Mbps, 17 Mbps, 4 Mbps, 3 Mbps

From the specs it looks like LPCM audio is recorded to both AVCHD and MP4. But the 5.1ch feature is only supported by AVCHD/28Mbps (at 23.98??).

Audio Recording system
Linear PCM (2ch)* / Dolby Digital (5.1ch when SM-V1 is used) * Feature supported only in the 28 Mbps/23.98 Mbps recording mode; resolution: 16 bits

This makes the same mistake as above, assuming that AVCHD and MP4 are just containers with the same codec. There are many parameters to the compression method used in MP4 and AVCHD that affect the quality, and bitrate is only one. Just because the bitrate is higher does NOT mean the MP4 is higher quality. For example, it may use less efficient compression (no CABAC, lower profile, fewer reference frames). Unless you know exactly what form of MP4 and AVCHD is implemented, there is no basis for recommending one over the other. Especially not just based on bitrate.

That's true, I'm assuming that Canon is using H.264/MPEG-4 AVC for the MP4 file, same as what they used in the previous XA10.

That's true, I'm assuming that Canon is using H.264/MPEG-4 AVC for the MP4 file, same as what they used in the previous XA10.

Please, again: H.264/MPEG-4 AVC is NOT sufficient to define what level and quality of compression is being used so how do you know if the MP4 is superior to the AVCHD? There are many parameters *within* this. Both AVCHD and MP4 use H.264/MPEG-4 AVC, but the parameters may be very different.

Does anyone know what profile is used in the Canon MP4 implementation? what for AVCHD? number reference frames? number of submacroblocks? b-slices?

Mark I know you are a LX7 user (as I am). In the specific case of the LX7 wich of AVCHD or MP4 for video do you prefer and why?

I am usually inclined to go for the higher progressive frame rate for smoother video, so that is AVCHD 1080p60. I have recently used the Panasonic high-zoom ZS30, which has both AVCHDp60 and 1080p30 MP4.

And, I was impressed with the 1080p30 MP4 implementation (even though no CABAC and lower profile). I shot MP4 because wireless remote shooting does not allow 1080p60. Here is a brief MP4 clip (shot by wireless remote):

Wireless-Remote Panasonic ZS30 HD Test Video - YouTube (http://youtu.be/9VmLrurzHMo)

Select 1080p.

And here is an AVCHD 1080p60 video:

Panasonic ZS30/TZ40 Test Video: Piano Playing Outdoors in Two NYC Squares on Vimeo

Both from the same camera. I think the video quality is similar in good light to the LX7, so this comparison should be relevant to that.

thank you Mark, as usual very nice work.
This one was recorded in MP4 at 1080, unfortunately the editing was not at top quality but at 940x540 , but I find it very efficient (as a travel camera editing on the road with often poor internet access) and easy for personal or web output.
Panasonic Lumix LX7 in Isla Mujeres Mexico - YouTube (http://www.youtube.com/watch?v=FriQrO2RUd4&feature=youtu.be)

My guess is the image quality between the two codecs will be close to each other. I can't see a reason for Canon to make the mp4 less quality than the AVCHD. The choice is probably there for your NLE and what it likes or your production environment.

Here is the info just in case anyone still cares:

Canon XA25 (should be the same as the XA20)

MP4 (.mp4):

GENERAL
Format : MPEG-4
General Format profile : Base Media / Version 2
Codec ID : mp42

VIDEO
Format : AVC
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=3, N=10
Codec ID : avc1

==============================================
AVCHD (.mts):

GENERAL
Format : BDAV
(no other info)

VIDEO
- Format : AVC
- Profile: : High@L4.2
- CABAC: : Yes
- ReFrames: : 2 frames
- GOP : M=3, N=30
Codec ID : 27
====================================


Main differences I see are the profile is very slightly higher for AVCHD (L4.2 vs. 4.1), and GOP structure. I have no idea what Codec ID "27" is for the AVCHD.

In real-world tests, I *think the MP4 seems to have noise in it, even with 0 gain and bright environment. I need to double-check. But it would seems like they should be nearly identical with MP4 being at 35Mbps w/ L4.1, and AVCHD at 28Mbps w/ L4.2.

I tend to shoot MP4 when I know I won't be doing much editing, and/or just want to upload it or something. AVCHD is better for editing and also has more timecode info. MP4 is missing both time/date stamp and the timecode. (Why they can't both have the same timecode info is beyond me.) Also, I shoot MP4 when I want to overcrank something. Wish this could have been in either mode.

So anyway, does this offer any insight into which one is better? Or has anyone had any real-world evidence they can share now?

-Tim

Oh, and here is a real "kick in the pants" ... or at least a monkey in the wrench:

I recently bought a 70D which is great for video, and actually looks better than my XA25's video overall (mostly because it is a bigger sensor, better lenses, improved shallow DOF, etc.), but as far as the codec, it is:

MP4/AVC, High@L4.1, and NO CABAC. And again, it looks at least as good, and often better. So codec isn't everything I suppose.

One thing not mentioned in this thread: It's very worthwhile testing the variations your camera provides in your usual NLE.

For example, IIRC the Canon XA20's version of MP4 requires timeline rendering in Premiere/Mac, while the AVCHD doesn't. Shoot AVCHD on this cam/NLE for better workflow. LPCM was mentioned above - this uncompressed audio is a good thing to have in many NLEs, and is better sound too.

Of course if I had a camera doing 1080p60 like Mark R. above, I'd probably use that quite a bit, even if it did require a little more work.

Tim K., no, codec isn't everything. CABAC is just another compression algorithm, packing more data into a smaller space. If you have more space, you can get the same quality at lesser compression/greater bitrate. The info you provided is virtually identical across that MP4/AVCHD implementation, but the biggest determining factor for quality will be bitrate.

h.264 levels are a little misleading. A "level" specifies the maximum samples, resolution, framerate, etc. That one version is MP4/4.1 and the other AVCHD/4.2 doesn't say that the specific 4.2 hardware codec in use actually *does* include any higher spec video than the 4.1 video. The real story for a camcorder's video codec is resolution, framerate, bitrate, and compression quality.

One of the best ways to try and break a codec is to point your cam at water that is being rippled by the wind. It can really stress the codec, as every pixel is changing on every frame. This should quickly reveal any macroblocking problems, where individual pixels get ganged up into groups of pixels, 8x8, 16x16, sometimes bigger, when the codec can't keep up.

The video quality isn't the only consideration. For example, I import AVCHD footage from my C100 into Avid Media Composer using the AMA function (which is importing the files directly without transcoding). It works well, without much lag when working with the footage.

However when importing MP4 files with AMA, it is almost impossible to work with the footage because it takes a good 4-5 seconds whenever I need to scrub through the timeline to a different position. Transcoding the MP4 files to Avid's native DNxHD codec solves the problem - but it takes a VERY long time to transcode (almost 1:1), even with a very powerful computer.

So knowing what file types your NLE works best with is also worth considering.

One thing not mentioned in this thread: It's very worthwhile testing the variations your camera provides in your usual NLE...
The video quality isn't the only consideration. For example...

...when importing MP4 files with AMA, it is almost impossible to work with the footage because it takes a good 4-5 seconds whenever I need to scrub through the timeline to a different position. Transcoding the MP4 files to Avid's native DNxHD codec solves the problem - but it takes a VERY long time to transcode (almost 1:1), even with a very powerful computer.

So knowing what file types your NLE works best with is also worth considering.
Um, right ;-)

Two examples from Jody's and my experience; sometimes finding a good workflow for your particular camera and NLE will make the decision for you!

As Jody points out, transcoding is always an option. This is worth considering if you find that the most time-efficient workflow for your systems sometimes doesn't provide the quality you want, EG,
Greenscreen compositing,
Heavy color correction or grading.
High-motion video, sometimes including movement from handheld work, as well as moving subjects.

Mostly, if you can get away without transcoding one of your camera's codecs, that's the one you want... until you run into a problem.