Most preferred way to stream to TV?

Hi StephenB

Thanks for sharing the results of your findings, I will try to relay what I initially realised about the converter (I will use your four point system to avoid confusion):

Point a) Believe it or not, a small minority of FLV files will play without the need for transcoding or converting but, unfortunately, the majority will not.

As for remuxing, apart from what I have just looked up, I must admit that I don't really know what that is. Consequently, if there is an automatic software tool that can "remux" a non-playable FLV into playable one then I would be more than happy to give it a go.

Point b) Yes, the screen sizes initially caused me a problem because my first couple of tries got me screen sizes of 1280 x 800 or ones that produced screen sizes that were too small for my screen, so by going through the various options I settled on 800x 480 as a reasonable compromise.

Point c) You said:

The tool also appears to be converting the frame rate from US film speed (23.97 fps) to US television speed (29.97 fps).

I must admit that I have not noticed any abnormalities when streaming files to my TV but as most TVs nowadays are made for the international market, have the ability to switch from US mode (NTSC) to UK (PAL) etc. then US film or TV frame speeds should not be a problem.

As a side issue, my Now TV box switches my TV into US coding mode by default.

Point d) As you probably guessed, I was not aware that the software tool increased the encoding from 400 kbits to 2 mbits, this is likely where the increase in file-size comes from.

Finally, if you can direct me to a remuxing tool that can change a FLV file to an MP4 (or playable FLV), especially if you have used it before, then I will be more than interested.

regards


UK Bob

The point on frame rate is that the original is ~24 fps, and it is being raised to ~30. The conversion tool does this by repeating every 4th frame - 1,2,3,4,5,6,7,8... is turned into 1,2,3,4,4,5,6,7,8,8.... This is called a 5:4 pulldown. Then it is spending bits encoding the duplicated frames that didn't need to be created in the first place.

Using a pulldown causes smooth motion to become somewhat jerky - this is called "judder" - which you can often see if you look for it. (btw - If you aren't seeing it now, then don't start looking for it. Once you start noticing it you will find it very annoying. Kind of like floaters in your eyes.).

On muxing:

audio and video are captured, and then compressed. The compressed bits are carried in "elementary" streams - one for audio, and a second for video. These elementary streams are then assembled into the file container -> in this case FLV and MP4. That assembly process is called "muxing".

With this particular file, the two elementary streams are completely compatible with MP4. So all that really needs to be done is extract those streams from the FLV and reassemble them into an MP4. That is called remuxing.

Instead, your tool is extracting the AVC elementary stream from the FLV, decoding every picture, resizing each picture from 624x352 to 800x480, applying the 5:4 pulldown, re-encoding the modified picture sequence, creating a new elementary stream and putting that new AVC elementary stream into the MP4. All the steps in italics are unneeded work, and can hurt quality.

Once again StephenB

Thanks for providing understandable explanations for how the conversion tool is increasing the frame rate, muxing and the extra unnecessary work the tool is doing.

Please let me know if there is a muxing tool that can "do away with" all the unneeded work and return playable files.

regards

UK Bob

If you can PM me a link your source FLV, then I can try that one specifically.

Hi StephenB

I just sent my PM to you.


UK Bob