Forum user: r11532

Edge,

I will get back later on to report on the outcome of these suggestions. It will take a few days to check them out. Until then.

lol

Edge,

I appreciate your suggestions and you don't need to apologize for being blunt. It's obvious that you have a great deal of experience and knowledge in this field and I will take all of your inputs seriously.

I have experimented with Spark flv, On2 VP6, Vp7 and VP8. In the beginning I was encoding my videos using VP6. At first I thought it was great. It was especially impressive at eliminating macroblocking, even in dark scenes. Eventually though, I noticed that some scenes had excessive loss of detail especially backgrounds having lots of green such as trees and lawns. There is segment in the movie Goodfellows where the loss in background detail was so bad its embarrassing.

VP7 and VP8 don't have this problem but when compared to h264, were no better in quality and were slower to encode. In the end, I reencoded my entire video library (a lot of effort) using x264. Macroblocking reduction was not as good as VP6 but the distribution of detail was much better.

As to the flv extensions on my videos. As you know flv is both an encoder and a container. Under the old Flash standard, use of h264 packaged in a flv container with an flv extension is perfectly acceptable (though under the new standard it's not recommended but isn't precluded). If the day comes when it is precluded (probably never), then I will have to switch to mp4 containers and extensions but until then I will continue using flv.

I used mp3 instead of AAC. Why, because I've been using mp3 for years and audio quality isn't that important to me. The extra audio fidelity at a given file size and bit rate achievable by AAC over mp3 is lost on all my home computers (especially laptops) and on my TVs which have very limited audio quality outputs.

The decisions I make in how I encode my videos and the settings I use are based on a combination of goals and constraints and experimental results. I want the highest quality possible achievable at 500kbs video constrained by encoding in a reasonable time frame. I have even experimented with encoding settings resulting in an encoding speed of 2 fps on my quad core 3.4 ghz machine. The outcome was almost identical to alternative settings that encoded at 75 fps. I would accept an encoding speed of 2 fps if the quality payback was there, which it wasn't.

As far as experimenting with x264 quality settings, I've mostly given up trying various combinations. Using a few simple virtualdub filter settings and x264 at its default settings produces a video image quality at 500 kbs that is nearly indistinguishable to that of the original vob at over 5000-6000 kbs (the loss in detail is so small that you have to enlarge the images 4x or 6x to see the tiny differences). I'm not suggesting that 500 kbs = 5000 kbs but the video image quality in almost 100% of dvds is so far below that suggested by their vob bit rates that 500 kbs ends up looking like 5000 kbs.

After solving my streaming issues, metadata issues, audio normalization and equalization issues, flowplayer configuration issues and lastly image quality issues, my final concern is the playback jerkyness issue.

I value whatever suggestions you can make toward resolving this remaining challenge.

lol

Edge,

I reencoded your http://vizmu.com/flash/bf-test.mp4 video using my standard script for encoding my movies giving the following results:

Analysis of bf-test.mp4   Analysis of bf-test.flv
source vizmu.com
encoder unknown           encoder x264
size 848x352              size 848x352
fps 23.976                fps 23.958
audio AAC mono            audio mp3 stereo
Video 938.35 kbs          Video 489.28 kbs
Duration 30.68 sec        Duration 30.72 sec
file size 3.70 mb         file size 1.98 mb

Download of my flv encode: http://r11532.freetzi.com/bf-test.flv

A side by side 6x blow-up of identical frames from each video suggests a very very tiny improvement in very fine detail at the higher bit rate.

At 6x the overall quality difference ranges from undetectable to almost undetectable depending on which frames are compared.

I ported both videos onto by movie server and played them back on my netbook computer to look for stuttering. Unfortunately the video itself jumped from scene to scene so quickly it was almost impossible to gauge if there was a difference. I'm going to download some movie trailers and conduct some additional experiments to see if there are any differences.

The script I used to compare the videos was:

<P><object id="flowplayer" width="100%" height="100%" data="flowplayer-3.1.2.swf" type="application/x-shockwave-flash">
<param name="movie" value="flowplayer-3.1.2.swf" />
<param name="allowfullscreen" value="true" />
<param name="allowscriptaccess" value="always" />
<param name="accelerated" value="true" />
<param name="flashvars" value='config={"clip":"bf-test.mp4"}' />
</object></P>

Yes, I'm familar with AAC audio, however, I've been using mp3 for so long that it's difficult to change. Also, my dozen+ audio tools are optimized for mp3 rather than AAC.

lol

Edge,

I will experiment with your suggestions. Some time ago I opted to use ffmpeg to wrap my mp4 videos and mp3 audio's into flv extension video files. At the time I was having problems streaming my mp4s and experiencing green screen issues. When I went to the flv container approach, the problems went away. Since the approach worked, I've stayed with it ever since.

Here is a sample.avi file. Its specifications are; Video: Xvid compressed, 720x304, 983 kbs., 23.976 fps. Audio: 22050, 16 bit, Stereo, PCM. Duration: 40 seconds. Additionally, the clip's original vob bit rate was 6140 kbs. encoded through virtualdub with filters msharpen settings of 120/15 and contrast boost of 112.

http://r11532.freetzi.com/sample.avi

lol

Edge,

Yes, I have done extensive experimentation with all the encoding suggestions you made and others (lots of others) but with limited success. Yes, I have tried hardware acceleration both on and off. I do use the most recent version of x264.

The change in the quality setting in flowplayer-3.1.4.min.js is the first major impact on jerkyness I've come across. In the last few minutes, I've also experimented with changing the setting to autolow and autohigh. I'm using my netbook (worst case) as my test platform for testing the various settings. I found that autolow appears to both retain low jerkyness while smoothing out the jagged edges.

Thanks for the quick feedback,

lol

For some time now I've been looking for a method to limit or prevent stuttering or jerky playback of my flv mp4 encoded movie videos. I have four different dual core 2 ghz+ computers, each of which experiences different degrees of jerkyness with movie videos authored at 720x480, 500 kbs, 23.976 fps, x264 encoding. I also have a .99 ghz netbook on which the jerkyness is so bad it's impossible to view any of my movie videos.

This forum and other web sites have provided quite a number of suggestions for reducing jerkyness including reducing the size of the video, reducing its bit rate, reducing its frame rate, changing to a different encoder. I have even made the suggestion to someone else in this forum to acquire a faster processor to solve the issue.

Recently by accident, I come across a possible solution that I would like some feedback on. To my surprise, this approach even allowed me to view my videos on my very slow netbook with almost no jerkyness.

The approach I use to display my videos includes the html script line: <script type="text/javascript" src="flowplayer-3.1.4.min.js"></script>

Embedded within flowplayer-3.1.4.min.js are many hundreds of commands one of which is: quality:"high". When I changed the "high" to "low", video jerkyness virtually disappeared on all my computers. The price for the reduction in jerkyness was that edges of video images especially displayed text became jagged. On the other hand the images did appear sharper and crisper.

Does anyone know of a website that gives a detailed explanation of what is going on when this change is made and why the jerkyness disappears? I came across a website: http://kb2.adobe.com/cps/127/tn_12701.html that discusses quality attributes assignable to Flash OBJECTs and EMBED tags. It lists a number of possible quality settings including low, autolow, autohigh, medium, high and best. Might these settings be applicable to the quality entry in flowplayer-3.1.4.min.js as well? If not, what might be the other quality settings, if any, besides high and low?

Any feedback would be appreciated.

lol

Despite the failed audio message, did the audio get muxed with the video?

If the wave conversion doesn't work, I'm out of suggestions.

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I don't know what format your audio is in but in general:

Among its many skills, ffmpeg also does audio/video muxing. You can mux the audio at the ffmpeg line.

For example if your audio is a mp3 and you just want ffmpeg to simply remux it with the video:

mp4box -add AFoldKora150.mp4#1 -fps 12.5 temp.mp4
ffmpeg -i temp.mp4 -vcodec copy -i AFoldKora150.mp3 -acodec copy temp.flv
flvmdi temp.flv AFoldKora150.flv /x /k
del temp.mp4
del temp.flv
pause

For example if your audio is a wav and you want ffmpeg to reencode and remux it to sample rate of 22050, a bit rate of 32kb and two channels:

mp4box -add AFoldKora150.mp4#1 -fps 12.5 temp.mp4
ffmpeg -i temp.mp4 -vcodec copy -i AFoldKora150.wav -acodec libmp3lame -ar 22050 -ab 32kb -ac 2 temp.flv
flvmdi temp.flv AFoldKora150.flv /x /k
del temp.mp4
del temp.flv
pause

lol

Joshua,

My mistake. I gave you inaccurate information. The bat file command for the line beginning with ffmpeg should have been:
::
mp4box -add FoldKora.mp4#1 -fps 25 temp.mp4
ffmpeg -i temp.mp4 -vcodec copy temp.flv
flvmdi temp.flv FoldKora.flv /x /k
del temp.mp4
del temp.flv
pause
::

You are correct, without the additional line content, the video will be reencoded into a large size poor quality flv.

As far as maintaining your original mp4 format instead of converting the video into flv; all the metadata injection tools I'm familiar with only work with flv files. It may be possible to metadata inject a mp4 but I can't suggest an approach.

lol

Try the code below or some variation of it or yours that includes:

scaling: "fit"

to see if it corrects the problem.

<P><script src="flowplayer-3.1.4.min.js"></script> 
<a href="video.flv" style="display:block;width:800;height:600" id="player"></a>  
<script> 
flowplayer("player", "flowplayer-3.1.4.swf", 
{clip: { 
url: "video.flv", 
scaling: "fit" 
}}); 
</script></P> 

lol

BlueToast,

I should have analyzed your situation in greater detail before giving defective advice on adding metadata. I downloaded your video file FoldKora.mp4 and successfully added metadata to it. In the process, I converted it to a flv file (that is used ffmpeg to 'wrap' the mp4 into a flv extension file). I've detailed the process below. Note that the video is not being reencoded just modified to run a mp4 with a flv extension, which is totally legal under the rules of flash file creation.
Steps:
Create a folder and add to it the following files (downloadable from the Internet):

- ffmpeg.exe
- mp4box.exe
- libgpac.dll (required by mp4box and is part of its
download)
- flvmdi.exe
- Your video file (for this instruction, I used your file
FoldKora.mp4)
- Convert.bat (not downloadable, use a text editor to
create a text file with a .bat extension containing
the following text contents):
::
mp4box -add FoldKora.mp4#1 -fps 25 temp.mp4
ffmpeg -i temp.mp4 temp.flv
flvmdi temp.flv FoldKora.flv /x /k
del temp.mp4
del temp.flv
pause
::

- Change FoldKora.mp4 above to your mp4 file name
- Change 25 above to your video's frame rate, this must be
specified.
- The 'pause' command keeps the bat file open when
finished so you can diagnose problems should the
conversion fail.
- The xml file that is created shows the metadata contents
that were added to the new flv.

Double click the convert.bat file to execute the conversion.

Be patient, it may appear that the conversion has locked up at the very end, but it's still processing.

The downloaded FoldKora.mp4 file didn't appear to have any audio. If you have audio you wish to add, then change the ffmpeg line above to something like:
ffmpeg -i temp.mp4 -i FoldKora.wav temp.flv or
ffmpeg -i temp.mp4 -i FoldKora.mp3 temp.flv etc.
depending on your audio file format.

I apologize for my earlier comment about flowplayer seeming to prefer flv over mp4. My comment should have been qualified and I should have said, based on my personal experience, flowplayer seems to like the flv extension over mp4. Early on (using version 3.1.0) I encoded my videos as mp4s but switched to flv when confronted with two problems I couldn't solve. The first was that I was unable to make my mp4s stream. The other was that when I clicked on a new point on the buffered time line, my screen turned green for the second or two that it took for the video to begin playing at the new point. Both issues disappeared when I switched to flv. Lastly, converting a mp4 extension to flv may be more complicated (as the steps above prove) than just changing the text mp4 to flv, though it sometimes works. And I agree that it could have been an earlier version of flash player making flowplayer seem to malfunction when it was 'not guilty.'

lol

My two personal favorites for metadata injection are 'FLV MetaData Injector' version 1.05 at: http://www.buraks.com/flvmdi/ and 'Yet Another MetaData Injector for FLV' version 1.4 at: http://yamdi.sourceforge.net/

I recommend using the gui that both sites offer as downloads.

Both are excellent at creating metadata. One key difference though, is that Yamdi doesn't create height or width fields. If this causes player problems, then use Flvmdi. If your video file has mp4 as its extention, you may need to temporarily (or permanently, flowplayer seems to prefer flv over mp4 extentions, even if encoded as mp4) change it to flv to perform the injection.

lol

When in full screen mode, depending on your script structure, flowplayer may expand the video to fill the available computer screen dimensions. Unless the screen's aspect ratio is the same as the video's, this will result in modest to extreme image stretching or squashing.

Use of the code below or some close variation will preserve the video's aspect ratio. Flowplayer will assign black bars above/below or left/right to fill in the extra space on the computer monitor when in full screen. It may be necessary to do metadata injection of the video to make it perform correctly. Experiment to see what works the best.

Also, it is generally good practice to make the video's horizontal and vertical sizes divisible by 16 even it results in a slight shifting in its aspect ratio. Thus, 800x450 would be more ideal at 800x448.

Without having access to your player script, I can't comment much on the possible causes of your lag problem. My personal experience with lag at the start of playing is that a large dimensioned, higher bit rate clip takes a few moments longer to begin playing than a clip that is less bandwidth intensive.

<P><script src="flowplayer-3.1.4.min.js"></script>
<a href="video.flv" style="display:block;width:800;height:448" id="player"></a> 
<script>
flowplayer("player", "flowplayer-3.1.4.swf",
{clip: {
url: "video.flv",
scaling: "fit"
}});
</script>
</P>

lol

When you say transfer bit rate, I assume it's bandwidth your interested in.

There are a lot of sites that can measure upload and download bandwidth to and from your web server. One that I use allows you to check bandwidth to most any place in the world.

Try:http://www.speedtest.net/ from your server. It should give a close estimate of your server's Internet connection capability.

lol

I looked at the video's metadata and noted that the datarate and FPS, the audio datarate, the file size, the video codec and the audio codec fields are all missing or not defined.

Though flowplayer can get some information directly from the video file, it does require some minimum direction from the video's metadata to properly play it.

You could try injecting new metadata using one of the free tools downloadable from the Internet to see if that will fix the problem.

Also, an approach that once was successful for me was to simply change the video's file extension from mp4 to flv and to also make the extension changes in the html and/or javascript.

lol