Our Free player does not support HLS playback, so only MP4 sources will play.
This also means that you will not be getting adaptive playback because the browser is going to start pulling down the MP4 video as a progressive download.
I guess the best thing to do would be to have multiple MP4s at different sizes available in the sources:  block of your player setup. This way the viewer can change the quality if they have a slower internet connection. Please see our code example at https://support.jwplayer.com/customer/en/portal/articles/1710454-configuring-multiple-sources for more details.
Thank you for this. Sorry for the delayed response - I only have just now seen the reply.
So to clarify... 1. When I see the video run on the free account, it takes 5 secs to adjust. The automatically generated thumbnail from the video also appears darker than I would expect. Is this a function of the free player and doesn't occur with HLS subscription levels?
2. Are the attributes I mention in (1) only occurring on an Apple platform? (I only have Mac so can't tell) I have created a video to show you what I mean. Here's the media ID: tMiwj1S3
3. I cannot actually find the link to the free player page. I had not spotted the MP4 option listed. Could you please point me to it?
4. Finally - Do I understand you correctly: You are saying that the video file size will determine the level of bufferring where there is poor bandwidths if only one file is uploaded. A bit like if you hosted on Amazon S3 and used the free player to display them. Just making sure I understand you.
5. I thought I read somewhere that the free player could no longer be used to self host. Am I mistaken?
1) I would have to see the actual file in use to know for sure why it takes 5 seconds to adjust. My first thought is that you have an HLS stream with five second fragments. Our player will not upshift until the end of the first fragment. The darkness is probably the default gradient that JW8 applies to your poster images, but if you do not like this, you can apply a custom CSS style to remove it.
2) Safari for Mac will play HLS streams with the Free version of our player because Safari has native support for HLS streams.
3) We removed the ability to create new Free accounts after JW8 was released, but it looks like you created your account before then, so you can continue to use your Free account. The MP4 sources are included in the JSON feed for each media ID: http://content.jwplatform.com/feeds/tMiwj1S3.json
4) No, that does not sound correct. When the player is playing an HLS stream and is in Auto mode, the level of buffering is determined by the viewer’s bandwidth and the width of the player. We will not upshift to a quality that is more that one quality wider than the current player. I know that is confusing, so here are more details:
If you have a 640px wide quality and a 720px width, but the player is only 500px wide and you have a fast internet connection, the player will upshift to the 640px width automatically but never to the 720px width, because we would be wasting those pixels and streaming usage.
If multiple MP4s are loaded as sources, we load the first source but the viewer can manually change sources via the HD button.
5) Correct, the Free player cannot self-host, so you will have to use the cloud-hosted players on your account.
Hope this helps. Please let me know if you have any other questions,
Hello again and thanks for these really thoughtful answers. I am pleased we have cleared up the free player question so I am only really concerned about the paid version options now.
1. It's just a standard old MP4 so darned if I know about segment numbers! However I am interested in your poster comment. Is this true for all players on all paid plans or was it just the free version that exhibited that behaviour?
2. Re the sources being included in JSON-LD. Would the captions be included in there as well, if added to the upload?
3. Re the bufferring your answer was actually very clear. Interesting insight. However, my question was really aimed at the free player scenario where JW wasn't creating (as I understand) multiple versions. My point was that you would have needed a small file to prevent (or limit) bufferring where there was poor bandwidth.