MP4 bitrate

[JRR]

Question re the bitrate in the MP4 file.

It seems to be just under 5500kbps. Is this the highest that is achievable ?

My camera outputs video at 48,000kpbs.

I am by no means knowledgeable in this techie stuff, but it is being suggested to me that the higher the bitrate the better.

I am having no issues playingback on my computer, but just wondering....

Thanks

Jim

[Lin Evans]

Hi Jim,

It's really a rather complex thing which has multiple variables. In essence and somewhat oversimplified, the larger the image (higher resolution) the higher the bitrate necessary for optimal playback. However there is much more to the equation than this. How much compression is being used by the video codec, what is the frame rate, and what device and resources available for playback ... These are all rhetorical questions, but are important when trying to determine optimal bitrate for your show. The other factor is how large a file size can your equipment handle? The higher the bitrate, the larger the file size. There is never an advantage to using a higher bitrate for playback than the original recording, but what you need to determine is where the trade-off lies and this has yet more variables. If there is limited animation in your video, the bitrate can be much lower without any perceptible loss in quality. Having lots of animation can sometimes overwhelm your system resources for very large file sizes such as 1080 p. Also the nature and type of player being used for playback also affects how well things will work with various bitrates.

The first thing I would do is to see how well your original video plays in your slideshow with the default camera bitrate. For "Custom" mp4 files at 1080p resolution, you can set the video bitrate as high as 24,000 with PTE. You can also set this bitrate at 60 frames per second. However, it's been shown multiple times that setting a really high bitrate rarely results in any real visible improvement in the MP4 created.

I would suggest reading the information in the link below to get a better understanding of how bitrate affects your video quality and why variable bitrates are sometimes a very good way to go with slideshows where both stills and video components may be present....

http://www.ezs3.com/...for_the_web.cfm

Best regards,

Lin

[JRR]

Thanks Lin

I hadn't discovered the "Custom" feature yet in PTE.

I'll read the reference you gave me and try to understand it all better.

Muchly appreciated !!

Jim

[potwnc]

My camera outputs video at 48,000kpbs

Hi Jim,

I'd be very surprised if it does. I think you're referring here to the audio sampling rate (which is very different from the overall bitrate).

As Lin said there's no "one-size-fits-all" for bitrate. If you can tell us a bit more about your shows and how they're delievred for viewing we can probably give you some pointers.

[JRR]

Hi Jim,

I'd be very surprised if it does. I think you're referring here to the audio sampling rate (which is very different from the overall bitrate).

As Lin said there's no "one-size-fits-all" for bitrate. If you can tell us a bit more about your shows and how they're delievred for viewing we can probably give you some pointers.

Not sure where I got the 48,000kbps.... I was intending to refer to the video, but I still got it wrong. (see attached screen capture)

Can't trust these luddites :rolleyes:/>/> :rolleyes:/>/>

Thanks for the offer of advice. I'm OK now, but if I hit an issue you can be sure I will be back. The forum has always been a great place to talk and resolve issues.

[goddi]

Not sure where I got the 48,000kbps.... I was intending to refer to the video, but I still got it wrong. (see attached screen capture)

Can't trust these luddites :rolleyes:/>/> :rolleyes:/>/>

Thanks for the offer of advice. I'm OK now, but if I hit an issue you can be sure I will be back. The forum has always been a great place to talk and resolve issues.

Greetings JRR,

I have mentioned this before in other postings, but this might be of help in getting more info from video and sound files. I like to use the MediaInfo program. It gives much more information about these files than the Windows Properties/Details tab. See the attached where I ran an mov in MediaInfo. Here is the site to download (free) if you want to try it out:

http://mediaarea.net/en/MediaInfo

Gary

[JRR]

Thanks Gary. I know where to go to get the details now (whether I will understand it all is another matter..... )

[PGA]

Jim,

At our age isn't the question: do we need to understand it all?

regards,

Peter

[JRR]

You are right Peter !!!!

Hope all all is well with you

[davegee]

I did a little testing today and varying the Bitrate seemed to make no difference in my test containing images panned across slides (no video).

However, varying the Frame Rate made a difference to the smoothness of the Pans.

MPEG4 Video.

DG

[potwnc]

Not sure where I got the 48,000kbps.... I was intending to refer to the video, but I still got it wrong. (see attached screen capture)

It would appear you got it from the "Audio sample rate." 48kHz (the same as 48,000 Hz) means that the original analog audio was sampled - to convert it to digital format - 48,000 times per second. That is the standard audio sampling rate for DSLR cameras that support video.

Your total bitrate (video + audio) is about 35,000 kbps (kilobits per second). So any output from PTE at 5,500 kbps will degrade the quality of the original. But whether you or anyone else will notice that degradation in either the audio or the video will depend on many factors including how good your sight and hearing is and how far away from the screen you are sitting.

As a very, very rough rule-of-thumb (because it depends on many things) a full HD video (1920x1080 resolutiion) should typically be in the range 10,000 kbps to 40,000 kbps for optimal playback quality.