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Topic: Quicktime 7 audio samples (Read 17554 times) previous topic - next topic
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Quicktime 7 audio samples

Reply #1 –
me wants avc sample
I know, that I know nothing (Socrates)

Quicktime 7 audio samples

Reply #2 –
Quote
me wants avc sample
[a href="index.php?act=findpost&pid=293310"][{POST_SNAPBACK}][/a]

Hmm, got some source material?

Quicktime 7 audio samples

Reply #3 –
Can you try the Fatboy sample @ 192-218?

Thanks.

Edit: Here is the wav file.

Quicktime 7 audio samples

Reply #6 –
Quote
http://multimediacom.free.fr/Download/ - Harry Potter 2 DVD trailer for sample QT7 AVC.  Ok?
[a href="index.php?act=findpost&pid=293382"][{POST_SNAPBACK}][/a]

Ok, but I don't want to do multiple encodes. Pick a bitrate, and I'll target that at the original frame size.

Quicktime 7 audio samples

Reply #7 –
900 kbit/s ( file size approx. 13,2-13,25 mb  13270 kbyte) and even possible best settings.  If you can crop black bars and keep  original resolution  without bars  720x304 and container must be *.mp4 because we don´t have QT7 to wacth *.mov

http://www.rapidshare.de/ Here you can upload  video max size. 28MB

Can you describe features of QT7 AVC? Some screenshots? speed, quality ...?

Quicktime 7 audio samples

Reply #8 –
fb2k isn't playing these for me.  i get this:
Code: [Select]
INFO (CORE) : opening file for playback :
INFO (CORE) : location: "file://C:\Documents and Settings\Reed Kerr\Desktop\sample_VBR_96_110k.mp4" (0)
ERROR (CORE) : error opening file for playback :
INFO (CORE) : location: "file://C:\Documents and Settings\Reed Kerr\Desktop\sample_VBR_96_110k.mp4" (0)
what do i need to play it?  i can play other .mp4 files...  im feeling kinda stupid here.  i know its probably a stupid mistake on my part.  it plays in itunes though...
a windows-free, linux user since 1/31/06.

Quicktime 7 audio samples

Reply #9 –
Quote
Can you describe features of QT7 AVC? Some screenshots? speed, quality ...?
[a href="index.php?act=findpost&pid=293387"][{POST_SNAPBACK}][/a]

Here are some screens:
First, the MOV export options. Pretty basic.


Next, the MP4 export options.


Clicking the "Video Options..." button brings up this window:


I'll work on the encode tonight. Initial impressions are that it's not a huge jump up from the current crop of MPEG4 encoders. I don't have access to Ateme's (?) H.264 encoder, so I'll leave that comparison up to others.

I'll work on the encode tonight. Quicktime Pro isn't the best way to work with video, so it may take some time. The better tools currently don't work very well with Quicktime 7.

Quicktime 7 audio samples

Reply #10 –
cool stuff


would be great if you could make both a mp4 and a mov sample with avc/h.264, with all options enabled (frame reorder, main profile, automatic keyframe, multipass, best quality)

i think a bitrate of ~600kbps would be representative for a relatively low bitrate, but still one where you should expect good quality

thx
I know, that I know nothing (Socrates)

Quicktime 7 audio samples

Reply #11 –
Ok, here's a 900k target encode. The crop process crashed Quicktime Player, so it's stuck with black bars on top and bottom. Not ideal, I know.

http://rapidshare.de/files/1445177/vts_01_8_900k.mp4.html

The setting I used were as above in my MP4 export options screenshots (except 900k target). Quicktime Player report 909k, so it looks like the encoder overshot by a bit. Encoding also takes an astonishingly long amount of time (computer is a Dual G4/867). I got tired of waiting after about 15 minutes, so I went to bed and let it finish.

Perhaps tonight I'll try a MOV encode at 600k.

Quicktime 7 audio samples

Reply #12 –
great, thx a lot!

my findings:
- the mp4 file uses slightly a variable framerate
- every frame consists of 5 slices
- max 1 b-frame in a row is used
- b-frames are set adaptively
- there are no multiple reference frames used
- no cabac used
- no loop used
- no weigthed prediction used
- no frame reordering used
- buffering period seis used

featurewise this stream is a baseline profile stream + b-frames, pretty poor imho...
qualitywise a lower bitrate needs to be used for testing, cause 900kbps is too high to really stress a codec imho

problems:
- the file crashes mplayer, videolan and ateme's mp4toolbox, which normally handle avc mp4 files fine
- the filebrand of the mp4 file is "mp42", it should be "avc1" i think
- there is a strange sdtp atom written, which isnt needed in mp4 and only consists of 00 08 00 08s

apart from that the file is played fine in directshow with ffdshow and the haali or nero mp4 parser
I know, that I know nothing (Socrates)

Quicktime 7 audio samples

Reply #13 –
Judging by that sample, it's a good thing this is the first revision.

Quicktime 7 audio samples

Reply #15 –
Quote
Ok here's the 600k encode (more like 625k   )

http://rapidshare.de/files/1475168/vts_01_8_600k.mp4.html

Export options were the same as the MOV screenshot above. The ouput was then passed through to an mp4 container.
[a href="index.php?act=findpost&pid=293927"][{POST_SNAPBACK}][/a]

thx, funny the stream is exactly the same as the 900kbps one, meaning
- same frames are same frametypes (i/p/b-frames...)
- same frames got vfr
- same features used (no cabac, loop, weigthed prediction)

only the bitrate differs
I know, that I know nothing (Socrates)

Quicktime 7 audio samples

Reply #16 –
Well, looks like they have some room for improvement. How does it compare to the current crop of H.264 encoders?

Quicktime 7 audio samples

Reply #17 –
Quote
How does it compare to the current crop of H.264 encoders?
[a href="index.php?act=findpost&pid=293951"][{POST_SNAPBACK}][/a]

- featurewise its clearly A LOT worse than most avc codecs, like x264 or nerodigital, which offer a much more complete implementation of the mainprofile (as i said: apples codec is more baseline profile + b-frames, as a main profile encoder...)
- also if basic things like cropping dont work than this means that you will loose quality you could easily save
- also a two pass encoder has to be able to hit the target bitrate on the spot
- i didnt really made a frame-to-frame comparison with other codecs, but the quality of the 900kbps encode didnt positively surprise me at all. at such a relatively high bitrate i would have expected a clearly good result and not a pricture that tends to blur on some parts. i wouldnt be surprised if x264 or nero provide better quality at the same bitrate, especially when you enable more advanced features like cabac, which are said to bring the bitrate down by about additional 10% losslessly (yeah losslessly)
i also made a quick compare with the 600kbps sample with nerodigital and apples codec tends to be clearly worse after a quick view

this whole sitaution reminds me that apple also only provided a VERY basic mpeg-4 part 2 encoder, only supporting simple profile...
i can only hope that apple will continue to work on their avc encoder and not leave it at it is now (for the marketing machine there is enough already it seems: vbr, b-frames...), so lets hope that their avc decoder at least supports the full main profile (cabac, loop, weighted pred aso...), cause if not i would say qt7 will be as useable for avc as it has been for mpeg-4 part2: not really useable 
I know, that I know nothing (Socrates)

Quicktime 7 audio samples

Reply #18 –
H.264 codec will be a mayor upgrade for QT  since MPEG-4 v2. H.264 much better than their old MPEG4-ASP. However quality is inferior to Nero H.264 and x264.
But it nice to see how a good technology as it is H.264 is taking a massive character.   
I really didn´t wait so fast implementation of H.264 (of course there were rumors about H.264 in 2004). Some commercials still trying to protect their codecs like Divx  and WMV9 and don´t introduce a new features and tending not to lose compability paying the price of low quality.
Well, one frase : H.264 is new standart.
What about future of the codecq? Well , main profile of QT7 H.264 seems not to be over yet (very basic features as was mentioned).  High profile?

Quicktime 7 audio samples

Reply #19 –
Not to change the subject from video or anything, but I noticed an interesting problem with the 128kbps CBR audio sample. Prior to QT 6.5.2, there was an issue with ringing in QT AAC files caused by the deletion of frequencies between 17 and 18kHz (very easily spotted on a spectrum analyzer.) Interestingly, my imagination "thought" that I heard ringing in this file as well, so I loaded it into Audacity. Sure enough, the famous frequency gap is back. I hope that this is simply a fluke, and that the version due for release has fixed this already.......

Quicktime 7 audio samples

Reply #20 –
Quote
Not to change the subject from video or anything, but I noticed an interesting problem with the 128kbps CBR audio sample. Prior to QT 6.5.2, there was an issue with ringing in QT AAC files caused by the deletion of frequencies between 17 and 18kHz (very easily spotted on a spectrum analyzer.) Interestingly, my imagination "thought" that I heard ringing in this file as well, so I loaded it into Audacity. Sure enough, the famous frequency gap is back. I hope that this is simply a fluke, and that the version due for release has fixed this already.......
[a href="index.php?act=findpost&pid=294092"][{POST_SNAPBACK}][/a]


Don't worry, nothing is wrong with the encoder.

I noticed the same as you so I encoded several other samples with various settings, and none of them had a cut-off. This led me to believe something was wrong with the original sample used in this thread, and yes, the wav itself has the frequency cut-off...

[span style='font-size:8pt;line-height:100%']edited for clarity[/span]

Quicktime 7 audio samples

Reply #21 –
Gah. Are they ruining their own encoder on purpose?