Best Quality For iPod TV and iPod H.264

[MacOSXAddict]

New to FfMpegx, but am looking for the best video quality under the iPod TV and iPod H.264 presets.

I am mostly interested in the what settings to have checked under the Options panel of these two presets to get the best quality and to reduce the resolutions blocks. Also wanting to know what QMin and QMax settings should be at.

If anyone could reply it would be greatly appreciated.

Thanks.....

Addict

[MacOSXAddict]

Anyone actually know which boxes to check under Options tab make the quality better?

[rumplestiltskin]

Best quality I've managed to get (which usually is fine):

Qmin: 3
Qmax: 30
Keyframe: 20
Decode with QuickTime (sometimes needed depending on the AVI source but I use it all the time).

The "Q" settings define the minimum and maximum "loss of quality" (so to speak) in order to keep a constant bitrate. If you drop the Qmin to 2, I've sometimes ended up with a bad file and it really doesn't provide any improvement (if the file is, otherwise, okay). The settings I use will increase the size of the file. You may increase the Qmax to decrease the file size but quality may suffer. Increasing Qmin WILL cause quality to suffer.

I believe the keyframe setting will cause a point where all the visual information will appear in the frame to occur more frequently. I think this also reduces a subtle "jump" I seem to detect when the keyframe interval is longer.

Video bitrate: ffmpegX might recommend something like 200kb but, if I have an action video or am looking for the best quality, I use 700kbps. This will also increase file size (dramatically).

Leave the other two checkboxes in the Options tab as is. Do not check any others. You might try using one of the "better" settings in the ME Function popup menu although I haven't quantified any difference yet.

Remember that H264 is 320x240, max. You may use a smaller height (for 16:9, for example) but keep it at a multiple of 16.

Sometimes a 320 x ### movie just can't be made as good as a 640 x ### movie. More pixels tend to be better. However, remember that H264 is a superior codec to the ordinary MPEG4 (that the iPod also will play). So, if you think you need to go up to the 640 pixel width, remember that the bitrate will have to be MUCH higher in order to compensate for the use of the inferior codec. Figure 2000kb (as opposed to 700kb for H264, for example).

Believe it or not, I've found that my old B&W movies I'm backing up to iPod format seem to look better in MPEG4 (at a higher bitrate) than H264. Something about how color images blend better in the human eye as opposed to how B&W images seem to require more sharpness and fewer artifacts in order to maintain quality.

Please post your results. Good luck!

[rumplestiltskin]

I should also mention that many times there are videos that look fine in the H264 at around 250kbps.

An important point I also did not mention in my previous post: All of my recommendations assume you will want to view your "iPodable" vids on your TV through your iPod and its AV cable, -and- that you're not watching them on a 42" plasma display. I watch on a 25" and 32" "old-fashioned" CRT TV and am satisfied with the videos I am producing.

[rumplestiltskin]

New info here:

https://forum.videohelp.com/viewtopic.php?t=290011

[MacOSXAddict]

Thanks for all the help rumplestiltskin, you really have been a life saver.

I just have one more question for you. I am encoding some avi's to the mpeg-4 format and am getting some compression artifact blocks in dark scenes. In bright scenes they are not present. Is there a way to eliminate the blocks or at least decrease them in the iPod for TV presetting?

Thanks

Addict

[rkelez]

Was gonna try out those settings and had everything in except that keyframe. When under the iPod h.264 setting i don't see a keyframe option available in options. There is that max GOP size, is that what you mean to set to 20? If not let me know please so I can try that out.

[danybrit]

i dont know why but im getting a fast-forward .mp4 using the ipod .h264.Does anyone knows why is that?

thanks a lot

[rumplestiltskin]

Max GOP: yes, that was what I meant instead of "keyframe". I'm not sure if this really has much of an effect.

Compression artifacts in dark areas: Yep, that will happen. As it's been explained to me, there are a limited number of "macro-blocks" in MP4 and even fewer in H264. Dark areas don't reproduce well in this scenario. It might be possible to boost bitrate but I don't know for sure whether this will offset the artifacts. Maybe if the spec changes and Apple's new iPod (the one we're expecting but hasn't been released yet) supports higher resolution, better quality (meaning a new H264 spec), we might overcome the artifact issue. It is possible an update to the iPod firmward (the 5G iPod) might permit such an improved "standard" to be used, as well.

H264 is still in its infancy, be patient and, if you wish, keep the AVI somewhere safe until H264 improves enough to trancode the file again using the better spec.

[danybrit]

But is it an error im making or what?
i dont understand because the movie plays in fast-forward until it finishes like at 30 minutes, when the movie is 1 hour and six minutes,is there anything i can be doing wrong?

i got something like this



ffmpeg version CVS, build 3277056, Copyright (c) 2000-2004 Fabrice Bellard
Mac OSX static build for ffmpegX
configuration: --enable-mp3lame --enable-gpl --disable-vhook --disable-ffplay --disable-ffserver --enable-a52 --enable-xvid --enable-faac --enable-faad --enable-amr_nb --enable-amr_wb --enable-pthreads --enable-x264
built on Dec 1 2005 03:50:24, gcc: 3.3 20030304 (Apple Computer, Inc. build 1666)
x264 [info]: using cpu capabilities Altivec
mp4 [info]: initial delay 0 (scale 23976)
Sun Jan 29 20:09:46 VET 2006
Input #0, avi, from '/Users/danieljsalas/Desktop/torrent's downloads/The 40 Year Old Virgin (2005) [ENG] [DVDrip]/The 40 Year Old Virgin (2005) [ENG] [DVDrip] CD1.avi':
Duration: 01:06:44.2, start: 0.000000, bitrate: 1466 kb/s
Stream #0.0, 23.98 fps: Video: mpeg4, yuv420p, 512x384
Stream #0.1: Audio: ac3, 48000 Hz, 5:1, 448 kb/s
Output #0, yuv4mpegpipe, to 'pipe:':
Stream #0.0, nan fps: Video: rawvideo, yuv420p, 320x240, q=2-31, 200 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Press [q] to stop encoding
error, non monotone timestamps 0 >= 7508
error, non monotone timestamps 0 >= 15015
error, non monotone timestamps 0 >= 22523
error, non monotone timestamps 0 >= 30030

[rumplestiltskin]

I'm guessing here but it might be related to the "timestamp" stuff.

I'd suggest that you try the encoding using MPEG Streamclip and see if this works. Don't use the 2-pass H264 and keep the bitrate at around 700kbps. Also make sure the framerate is 29.97 (or 30).

[rkelez]

I see that problem all the time when I don't check the decode with quicktime option in the options tab. Not sure why it happens but yeah its like the video runs at 2-3x its normal speed. Try doing all your same settings but this time make sure you check the decode with quicktime option

[rumplestiltskin]

If the AVI can be played properly with QT Player, I always check the "Decode with QT" checkbox even though it may not always be necessary. I've found this eliminates unexpected issues.

[danybrit]

Ok i'll try to decode with quicktime ,i'll post the results here

thanks

[rkelez]

Ok tried out some of your recommended setting rumple and the result is impressive in quality and size, but it won't transfer to the ipod like many others have been reporting. I tried a direct drag to the ipod (through itunes window onto the ipod icon) to no avail. Settings were iPod h.264, 400x176, 29.97 fps, 48khz & 160 kbps audio. In options i was aiming for best possible so i checked on left: constant bitrate, i4x4 analysis, decode with quicktime. on right: avc level 1.3, ME function exhaustive, max GOP 20, Q 3-30.

Those settings all meet the ipod specs to my knowledge but won't transfer over through itunes by drag or update, any ideas or tricks to fixing that little transfer issue?

Also in that options tab anything aside what i already set that will improve quality?

[rumplestiltskin]

Do you have your iPod set to sync automatically? If so, you may not be able to manually drag in a movie. I never sync; I only do a manual update by dragging whatever I want into the iPod (directly to the iPod within the iTunes interface).

The other specs seem correct. I haven't done the "exhaustive" ME setting but I doubt that's causing a problem.

Do -not- check any of the other checkboxes (in Options) or you will produce a file that won't transfer to the iPod at all.

[rkelez]

Yeah have it set to manual when I try to drag it onto the ipod through the interface.

[rumplestiltskin]

What does ffmpegX show if you click the "Info" button about the source file?

[rkelez]

Video: [Xvid] 576x256 12bpp 25.000 fps 799.1kbps (97.5 kbyte/s)
audiocodec: framecopy (format=55 chans=2 rate=44100 bits=0 B/s=13166 sample-0)

[danybrit]

Hey guys i checked the the option of decoding with quicktime ,but now i got no audio at all.What can be wrong ,i tried all with the audio but nothing,it was ACC

what can i try to fix it?
thanks a lot

dan