MP4 or FLV? Pros, Cons, and Video Exporting Suggestions

Hi everyone,  (hoping you can help demystify a few video questions below)

We've used a small amount of video in our past Articulate projects, relying on FLV and some YouTube embeds.

We're working on a new project that requires multiple video clips and I keep reading on the forums about the use of MP4 h.264 encoded videos over FLV. 

We exported videos out of Vegas Video, then converted them to FLV.  We uploaded them to a test server and the playback was surprisingly fast, no delay before starting to play. Hurray!  You go, FLV!

Curious, we exported MP4 versions straight out of Vegas Video.  The MP4 file sizes were a bit smaller than the FLVs, but the playback was nowhere near as good. There's a long delay before playback begins, to the point where you doubt the video will ever start.

Debating whether we should just stick with FLV or are we doing something wrong with these MP4s?  Would a pre-loader be the answer?  Or stick with FLV and a pre-loader for even more assurance?

Is it accurate to say that FLVs basically stream via a progressive download, and MP4s must download in their entirety before playback begins?

What video format have you had the most success with, and what settings do you use when preparing the files for Articulate integration?   Thank you!

I'm going to include the file info from Format Factory for both the FLV and MP4:

(One thing I'm noticing is the frame rate difference below, and the audio bit rate...)

Format                           : Flash Video
File size                        : 10.3 MiB
Duration                         : 1mn 44s
Overall bit rate                 : 828 Kbps
Encoded date                     : Wed Jun 29 16:42:04 2011
Tagged date                      : UTC 1970-01-16 03:43:03
Tagging application              : Turbine Video Engine SDK

Format                           : H.263
Codec ID                         : 2
Codec ID/Hint                    : Sorenson
Duration                         : 1mn 44s
Bit rate                         : 768 Kbps
Width                            : 427 pixels
Height                           : 240 pixels
Display aspect ratio             : 16:9
Frame rate mode                  : Constant
Frame rate                       : 29.970 fps
Bit depth                        : 8 bits
Compression mode                 : Lossy
Bits/(Pixel*Frame)               : 0.250
Stream size                      : 9.61 MiB (94%)

Format                           : MPEG Audio
Format version                   : Version 1
Format profile                   : Layer 3
Codec ID                         : 2
Codec ID/Hint                    : MP3
Duration                         : 1mn 44s
Bit rate mode                    : Constant
Bit rate                         : 48.0 Kbps
Channel(s)                       : 1 channel
Sampling rate                    : 44.1 KHz
Compression mode                 : Lossy
Stream size                      : 672 KiB (6%)

------------------ MP4 Details --------------

Format                           : MPEG-4
Format profile                   : Base Media / Version 2
Codec ID                         : mp42
File size                        : 10.0 MiB
Duration                         : 1mn 43s
Overall bit rate                 : 887 Kbps

ID                               : 2
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : Main@L2.1
Format settings, CABAC           : Yes
Format settings, ReFrames        : 5 frames
Codec ID                         : avc1
Codec ID/Info                    : Advanced Video Coding
Duration                         : 1mn 43s
Bit rate mode                    : Constant
Bit rate                         : 768 Kbps
Width                            : 428 pixels
Height                           : 240 pixels
Display aspect ratio             : 16:9
Frame rate mode                  : Constant
Frame rate                       : 59.940 fps
Original frame rate              : 29.970 fps
Standard                         : NTSC
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Interlaced
Scan order                       : Top Field First
Bits/(Pixel*Frame)               : 0.125
Stream size                      : 9.33 MiB (85%)
Language                         : English
Encoded date                     : UTC 2011-07-10 23:45:22
Tagged date                      : UTC 2011-07-10 23:45:22

ID                               : 1
Format                           : AAC
Format/Info                      : Advanced Audio Codec
Format profile                   : LC
Codec ID                         : 40
Duration                         : 1mn 43s
Bit rate mode                    : Constant
Bit rate                         : 128 Kbps
Channel(s)                       : 2 channels
Channel positions                : Front: L R
Sampling rate                    : 44.1 KHz
Compression mode                 : Lossy
Stream size                      : 1.58 MiB (14%)
Language                         : English

21 Replies
Phil Mayor

Hi Kevin

There is an issue with some MP4s that puts the file information at the end of the file instead of the begiinning which is why they need to download fully beofre playing.

there is a fix for this, however the articulate player will not start an MP4 until it has been fully downloaded whatever you do.

It looks like your framerate is different because it is interlacing the output


Kevin Thompson


We did a quick test with our target audience using the MP4s, and the consensus was that they took too long to begin playback. We switched back to the FLVs and are using the bulk pre-loader available for purchase over at

We found that the pre-loader doesn't help Firefox users, as that browser re-downloads the video even after pre-loading it in the cache. IE does a better job of retrieving the cached video.

The reason we didn't opt for a service like Vimeo or YouTube is because we wanted to sync some other slide objects with the video playback. As far as I could tell, the only way to do this reliably is to embed the video (in our case, as FLV for best playback speed).

Let us know what route you go!



Originally was going with the FLV but it was pixelating and looked amateur so I switched to MP4 which looked great but to your point - took forever to load. About 15 minutes ago I tried converting the good lookin MP4 to FLV and it's working fine now. Unfortunately I have about 4 days of back and forth, searching the forums, and converting video that should have been easy as one click.  Maybe Articulate doesn't put MP4 as an option if it's going to be ridiculously slow to load...

Thanks for your response.

Phil Mayor

MP4s should load fine the main problem is the encoder puts the atom file at the end, so it needs to download the whole file before it can play

You can move the atom manually to the beginning, but I think the problem still persists, a it doesnt progressively download!

Not sure why, adobe updated their player to progressively download mp4s but articulates doesnt seem to play yet

Kevin Thompson


How do you manually move the atom file to allow progressive download of MP4s?  Are you saying that if the MP4 is rendered using Adobe's tools that it should work, or does it still not progressively download when used as part of an Articulate presentation, regardless of the tool used to produce the MP4?

I thought we had tried the Articulate Video Converter and a couple of other tools, but I know we didn't do anything with an atom file.



Annette Whitby

Hmmm . . . Having a similar issue with a slow loading MP4 video. It takes about a minute for it to load in the Presenter Player. I'm having trouble understanding Phil's instructions included below.  Can anyone re-explain how to troubleshoot this issue?  Is it caused by an "atom" file???


Phil Mayor said:

Kevin, you need this adobe updated their flash latest player to stream MP4s, if the atom file was at the start, Articulate does not seem to "stream" even then though, I know Dave Mozealous has said it should, but I have never managed to get it to work.

Peter Anderson

Videos in Articulate Studio ‘09 content will progressively download, so that users will not have to wait for the entire video to be downloaded to their computer before playback begins.

In some cases, however, an MP4 file may not be properly formatted to allow progressive downloading, which means users would have to wait for the video to be fully downloaded before it begins to play.  If you have an MP4 file that is exhibiting this behavior in your published content, you may be able to correct it.  Here's how.

Jasmine Francois-Moore

Hello Everyone,

This may have been already answered but because of the information gap I thought I might just ask.  I have a 7 minute screencast of a platform I am training users on completed in Articulate Storyline.

I want to convert this to do I do it?

For example if I wanted to load my screencast storyline into youtube or just run as a standalone video.  What is the easiest way? 

Thanks in advance!