In Adobe Media Encoder is there a way to match the source frame rate if it isn't in the list?

Enthusiast ,
Oct 18, 2017 Oct 18, 2017

Copy link to clipboard

Copied

On rendering with Adobe Media Encoder, from an After Effects project which uses a 20.0 fps frame rate (there are other videos from the client that also use non-standard frame rates that I colud have chosen), Media Encoder with "Match Source" selected puts the frame rate at 23.976 fps instead of 20.0 fps (the actual source frame rate). Note: I am rendering to the H264 codec.

1) Why does Adobe Media Encoder not match the source frame rate in this case? It says "values may be constrained by the output format" but as far as I know, there is nothing about the H264 codec that limits it to just what Media Encoder has in it's very limited list box of 12 frame rates. Note. 20.0 fps isn't in the list box. Nor are other frame rates which I have also wanted to use. What if I want to use any frame rate from eg. 5.0 fps to 120.0 fps for outputting with H264? Note: The original source video the client sent is AVC (same as H264) High@L3.1, 20.0 fps.

2) Is there any way to make Media Encoder use the correct frame rate for this project (20.0 fps) instead of 23.976 (which will surely lower the quality).

Views

5.6K

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Adobe Community Professional ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

No, there is not a way to match a frame rate that is not in the list.  You can only pick from the ones that appear in the pop-up menu.

If you happen to be running macOS, you can render to QuickTime Photo-JPEG at best at pretty much any frame rate you want (including 20 fps).  Then, open that file in QuickTime Player X and export to 1080p (or any of the other sizes like 720p and down).  The resulting file will be H264 at 20fps.  You can change the .mov extension to .mp4 as well.

I'm have to ask:  With several well established frame rate standards, how did you wind up with 20 frames per second?   Granted, I get that there are some interesting numbers out there (like 7.5 GPS for Real Video in the 1990s), but lower frame rates are almost always multiples of the standard rates (so, 10, 12, 15).

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Enthusiast ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

Thanks for your reply, though I'm on a PC so I can't use some of your suggestions.

As mentioned it's a clients video/videos that I'm working from. He wanted green screen replacement done on one of 3 the videos he had encoded and wanted me to pick one of them to do. These are the specs of the original files (before I did green screen replacement) according to Media Info:

Writing Library: Apple Quicktime

Res: 1080x720 (3:2)

1 video at 16.997 fps, 1 video at 16.991 fps, 1 video at 20.000 fps.

I don't know why they're the odd resolution and frame rates. I suppose I could have asked the client but I wasn't sure whether I should. The client liked the video produced but he's not the end client and the end client could want changes. They also never specified where they wanted them played but I assume internet, but at least 23.976 fps will give more options to play it in more places (maybe some sites only accept certain frame rates up to their max eg. up to 60 fps?).

edit: In another view in MediaInfo (Text View), two of the client's videos say "variable frame rate" and one says "constant". And it says "Original Frame Rate: 25 fps". So I'm a bit confused about what happened there. Maybe they were shot at 25 fps but then the client (or his client) encoded them into odd frame rates/variable frame rates.

But really Adobe Media Encoder (and AE) should allow practically any frame rate because there can be reasons why they are needed, even if they're not the final frame rate for the delivered project. There's no reason why H264 has so few. H265 (HEVC) has more but still not ones that matched the source videos the client sent (eg. 20.0 fps etc.). Also, HEVC in Media Encoder allows up to 300 fps but After Effects only allows comps up to 120 fps. There could also be reasons why you want very low frame rates like 5 fps (eg. if you're trying to remove judder caused by dropped frames in a low fps video by interpolating them or maybe for a slide-show etc.).

The codecs themselves only care that the data rate stays within the allowed range and for frame rate that it is 1 number (integer) divided by another (as far as I know) eg. 24000 & 1001 for 23.976 fps? So I think i'ts just 2 numbers so the user should be able to enter them if they're not in the list currently. It should also give you an option to encode to a particular frame that you don't want stored in the list (eg. because it would be so rarely used) - ie. to just type in a frame rate instead of it only allowing you to select from a limited list.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Adobe Community Professional ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

Some formats do allow you to set whatever frame rate you'd like (QuickTime being the best example that I know of, assuming you've chosen a CODeC that allows it).

Most other formats are standardized with specifications that must be adhered to.  It's what guarantees that you can go from source footage settings, to edit settings, to edited master settings to delivery settings and have files that play as expected.  Going against that is "out of spec".  For example, DV-NTSC can only run at 29.97 or 25.  There's a 24p variation, but it has 3:2 pulldown while on DV tape and can only be removed/pulled up on the computer.  If going back to tape, 3:2 pulldown had to be put back so that it's running at 29.97 again.  DVD-Video is about the same.  If at any point in a workflow an out of spec frame rate is introduced, then the footage cannot be recorded back to DV tape or the duplicated/replicated DVD-Video title will not play as expected in a DVD-Video player.

The common numbers of 24, 30 and 25 are based on analog formats and the frame rates available in AME's pop-up menu are based on those numbers as well (most being some variation of those).  These and their variations were established for things like picture playing in sync while interlocked with audio, timing a program accurately to the hour, keeping color in phase, functioning with power systems (60Hz, 50Hz).  (I'm sure there's more that I'm not listing.)

If a client is giving you out of spec files, it's common to bill for the time it takes to remaster/conform the footage.  If it's a really "good" client, you could list the time it takes to conform the footage on your invoice as "no charge".  Although, one could argue that a good producer would go with format standards, including frame rate.

After Effects will allow you to enter pretty much any frame rate you want.  It used to be capped at 99, but is now 999; however, that's for flexibility with temporal resolution while in After Effects only.

Getting back to specifications, some CODECs have strict frame rate requirements while others do not.  There's usually a white paper available by whomever published the CODEC that details this.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Enthusiast ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

Thanks. I was wrong about the max frame rate for After Effects (ie. it being now 999 fps not 120 fps, at least in CC 2017 - I assume it's the same in CC 2018). I looked at the max in the list box which was 120 fps. Though there are still consumer(ish) cameras that allow frame rates of 1000 fps etc.

I'm looking at the H264 specs (on itu.int) and I only see maximum frame rates depending on various luma widths and heights and H264 levels (eg. for 4Kx2K at level 5.1, max fps is 30.0 fps. (I thought it was higher but maybe that's H265).

But for H264, according to that document the frame rate seems to be represented by "time_scale" (eg. 30,000) and "num_units_in_tick" (eg. 1001), eg.  30,000/1001=approx 29.9700299... fps. So it seems you can set those two variables (time_scale and num_units_in_tick) to any reasonable number to represent any frame rate up to the maximum frame rate depending on the H264 level and width & height in luma samples. eg. if it's progressive I don't see why any reasonable frame rate can't be used. ie. there's nothing limiting it to the specific ones chosen in Adobe Media Encoder - if it can be represented by those two integer variables (and within certain limits, depending on the H264 level etc.) it should be okay.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Adobe Community Professional ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

While it should be okay, it would be out of spec in most cases.

The rule of thumb for reducing frame rate is going with a whole number that when divided into the full frame rate are also a whole number (there might be an easier way of saying that).  So, 24 would reduce to 12, 8, 6, 4, 3, 2 or 1, but not anything higher than 12 nor 11, 9, 7, nor 4.  29.97 seems fine converting to 14.985, 15, and 10.

Or let's put this another way:  If you go with a standard frame rate, your workflow is good to go from source footage to edited master and delivery.  If you go with a non-standard frame rate, you're not good to go.

We have similar considerations with frame size.  Sure, you could create your animation at 2,000 x 611 at 99 fps in After Effects, but exporting at those settings will require a format like Animation or Photo-JPEG compressed QuickTime.  If sending a quick H264 sample of this to a client, you'd need to nest into a standard size Comp like 1920x1080 and do a "Fit to Comp Width" with the frame rate of the containing Comp at 29.97, 25, 24 or 23.976.

Speaking of high frame rates, have you seen that TV show with the two guys who shoot with a camera that does something like 10,000 fps?  It's stuff exploding and shattering.  I can't remember the name of it.  Humming birds and bees can be fun to shoot at 240.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Adobe Community Professional ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

Another factor affecting H264 is that you have a GOP structure (group of pictures) that's inherent to interframe compression.  I'm much more familiar with the details of MPEG2's GOP structures and variations.  I remember the minimum being 4 and the highest being 15.  So, your MPEG2 encode would run at 29.97 or 25 with a GOP of 4 if you wanted it to (the result would be a larger file than if it was GOP 15).  The details about H264 and it's GOP settings have to be out there somewhere.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Enthusiast ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

Speaking of high frame rates, have you seen that TV show with the two guys who shoot with a camera that does something like 10,000 fps?  It's stuff exploding and shattering.  I can't remember the name of it.  Humming birds and bees can be fun to shoot at 240.

If you mean Mythbusters I've seen quite a few of those where they sometimes would shoot with very high fps, but if it's not I don't think I've seen that show (maybe it's not available in the UK). Though I've seen other TV shows with very high fps and on youtube (obviously normally slowed down. I've not seen anything natively shot at >120 fps playing back >120 fps).

re: Frame rates, I still think that Media Encoder is making their own limitations for what frame rates are available for what codecs when a lot of the time they shouldn't. Even though some devices or websites may be limited to some (but they could and do have specific presets for certain devices eg. Blu-ray), for where it isn't limited by a particular device, Adobe shouldn't add limits where they are unnecessary (they can always highlight the most common frame rates in the list but still allow any supported by the codec (and any level within the codec)).

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Adobe Community Professional ,
Oct 19, 2017 Oct 19, 2017

Copy link to clipboard

Copied

LATEST

Yes, Mythbusters.

For what it's worth, if you can find a way switch your workflow to QuickTime, then you're good to work at the off-spec frame rates in After Effects and QuickTime Player.

Interestingly enough, ITU has a video on their home page about standards: ITU Standardization – The technical foundations of the Information Society - YouTube

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines