Pandora For Kids: Looking For A Kind Soul To Test Video Playback

[timothee]

Hi there,

Sorry this is another "video playback" thread, but I'm not looking for generic info, I have a specific case I'm looking answer to.

Some background: I have a 3-weeks trip planned in August (Singapore-France: 14 hours flight!), with my 2 year old twins. I assume by then I'll have my Pandora, which I intend to use for video playback:
1) in-flight to entertain the kids
2) video-ed out in France to show the kids some telly once in a while

I've started ripping my cartoon DVDs (cute Canadian cartoon called "Caillou") and I need to be absolutely sure these will play smoothly on the Pandora. I'm currently converting to the following specs:
* h264 - 704x480 - 29.97fps - 600kbs (intended for playback at 704x540, scaled down playback on pandora screen to 624x480)
* dual stereo audio tracks, vorbis q4 (~128kbs)
* mkv container

From what I've read, I'm not worried about codec/format support, but rather plain "can these files play smoothly on the Pandora?". I'm 90% sure they will play fine, but before I convert my whole collection, I've uploaded two of the episodes I have already ripped, in the hope someone could confirm they will play ok on the Pandora.

caillou_01_Les_Bandes_Dessinees.mkv (~20MB)
caillou_02_A_La_Bibliotheque.mkv (~40MB)

Thanks for anyone who can give me a definitive answer.
Tim

 

[.Gogeta§§J4BR.]

caillou is nice

congrats on caring about what your kids watch

I cant help directly because I have no pandora, but judging from the fact that mplayer is the app that got ported, and mplayer can run matroska...

 

[Alpha2]

I think the problem is there's no real way to know if Mplayer or which ever you can download the first day will be fully compattible with the MKV containiner or even things like the H264 codec. Some say it's as simple as having the codec but what if the codec has to be tweaked to run a video on Pandora just like the player may need to be tweaked?

From what I've read it would seem logical that even without extra codec or DSP support it should be possible to play the resolutions you're encoding, but if I wanted to be absolutely sure that a generic player, that hasnt been updated with the latest addons, would play my movies I'd probably stick to things like MP3 audio and XviD until the thing comes out and you KNOW that the suport is there.

of course there's also the possibility that you could just make ISOs of the DVDs and maybe Mplayer could play them raw or something (I dunno, I have players on my laptop that can do that but I dont know what Mplayer's full capabilities are...) just food for thought, I'm far from an expert.

 

[Chip]

I can't give you more than a "probably" on 480p h.264 right now. There's a solid chance we'll have good h.264 codecs built into a media player by then, but I can't promise it.

If you want assurances, I can assure you that, as Alpha2 suggested, divx/xvid video and MP3 audio will work like a charm. It will also use significantly less CPU power than h.264 and allow you to watch more videos on that long flight.

In addition to using a less demanding codec, encoding at a lower bitrate will also increase battery life. No point encoding a cartoon for 2-year-olds at full resolution - go to 2/3 or even half rez. You will have to play with the bitrate a bit, but cartoons (especially ones with large patches of solid colors like this one) encode very well. You should be able to cut it down to 300-400kbps and maybe get in a couple extra episodes on a charge.

 

[notaz]

I'll try this on a devboard today if I don't forget.

 

[Yod4z]

H264 maybe to heavy if you use CABAC option.
I think the same resolution with Xvid could be played smouthly on Pandora but x264 need maybe the help of the DSP (is not already done)
720p with xvid codec video are played nicely on Beagleboard (same Soc as the Pandora)

 

[cosurgi]

No point encoding a cartoon for 2-year-olds at full resolution - go to 2/3 or even half rez.
You are right about other points, but with this one I don't agree. The kids' eyes are even more valuable than yours (don't they?). Therefore they should get the best resolution that you can give them.

I changed my mind not longer than a year ago - I was used to seeing crappy cartoon quality and I thought that it can't be better. But OTOH when watching movies myself I was always making sure that I get the best quiality I could from my ripped DVDs. And then my wife bought movies for kids on DVDs (which I ripped afterwards). And suddenly I saw that it is possible for a kids' story to be of high quality. And suddenly my opinions changed completely. Now I prefer to give them the highest quality too.

I'm converting all movies to divx (mpeg-4) with this script, using lavc:

CODE

#!/bin/bash
# USAGE: $1 is the input file, $2 is the output file
cd `dirname $1`
mencoder `basename $1` -o $2 -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1900:vpass=1
mencoder `basename $1` -o $2 -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1900:vpass=2
rm divx2pass.log

Two pass encoding and bitrate of 1900. You can edit it up to your taste. Sound bitrate is 128 here. Mencoder will read ANY format and save it as divx.

If you want specific size you can add CODE
-vf scale=720:544
, like this:

CODE
mencoder `basename $1` -o $2 -oac mp3lame -lameopts abr:br=96 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=2200:vpass=1 -vf scale=720:544
mencoder `basename $1` -o $2 -oac mp3lame -lameopts abr:br=96 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=2200:vpass=2 -vf scale=720:544



Also, when ripping DVDs there's very often a black border around the movie, and it's best to cut it off, because it is affecting quality very much (it eats a lot of bitrate - sudden changes in th epicture, like this border require more bits for fast fourier transform). Also here I am scaling the cut movie to 800 pixels width, preserving aspect ratio (800:-2), because that's the width of our wall projector.

CODE

#!/bin/bash
#USAGE: $1 is the DVD ripped file, it must contain either "DVD_" or "_DVD" in its name - this part is cut off to generate the output filename

current_path=`pwd`
current_name=`basename $1`
new_name=`echo $current_name | sed -e 's/DVD_//g' | sed -e 's/_DVD//g'`
new_path="`dirname $1`/`basename $new_name .avi`"

# 1. make directories - encode everything into a subdir:
mkdir $new_path
mv $1 $new_path
cd $new_path

# 2. detect the black border to cut it off:
mencoder $current_name -o $new_name -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=2700:vpass=1 -vf cropdetect=100:2,scale=800:-2 2>&1 | tr '\015' '\012' | grep 'vf crop' > $new_name.CROP

crop=`cat $new_name.CROP | sort | uniq --count | sort -rn | head -1 | awk -F( '{print $2}' | awk -F) '{print $1}'`

# 3. we know the border now
echo $crop > $new_name.CROP_result

# 4. make sure that there wasn't any error in border detection
if ["0$crop" = "0" |]; then
exit 1
fi

# 5. clean before real encoding
rm divx2pass.log
rm $new_name

# 6. begin real encoding, with border cutoff
mencoder $current_name -o $new_name -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:autoaspect=1:vbitrate=2700:vpass=1 $crop,scale=800:-2
mencoder $current_name -o $new_name -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:autoaspect=1:vbitrate=2700:vpass=3 $crop,scale=800:-2
mencoder $current_name -o $new_name -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:autoaspect=1:vbitrate=2700:vpass=3 $crop,scale=800:-2
mencoder $current_name -o $new_name -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:autoaspect=1:vbitrate=2700:vpass=3 $crop,scale=800:-2

# 7. clean afterwards
rm divx2pass.log

# 8. don't delete anything, just move to a subdirectory, in case if the original is still needed

mv $new_name ..
mkdir ../DVD
mv $current_name ../DVD/; mv $new_name.CROP ../DVD/; mv $new_name.CROP_result ../DVD/
cd $current_path
rmdir $new_path




The bitrate is 2700 and sound bitrate is 128. I used this script to encode planet earth DVDs into resolution of our projector.

When you copy paste this script - make sure that the "wrapped" lines are a single line! By "wrapped" I mean text being wrapped because forum text is not wide enough (try decreasing font size in your browser, and you'll see).

 

[clippa]

If you want the best quality, it's best to preserve the vertical resolution and stretch the horizontal to the desired aspect ratio so a pal mpeg which is 16:9 and say 720x576 would become 1024:576.
The pandora's res is 800x480 though, so for 16:9 I would resize to 800x450, or if you want to fill up the screen a bit more you could resize to 848x477 and then cut 24 off both the left and right. Xvid with target quantizer set to 4 seems to be a good compromise between quality and file size if you're going with avi.

 

[cosurgi]

If you want the best quality, it's best to preserve the vertical resolution and stretch the horizontal to the desired aspect ratio so a pal mpeg which is 16:9 and say 720x576 would become 1024:576.
I'm not comfortable with non-square pixels. Assuming that I watch the movie at good aspect ratio, it means that there's some horizontal scaling going on during playback. I prefer to just give a higher bitrate, it should be equivalent, shouldn't it?

Xvid with target quantizer set to 4 seems to be a good compromise between quality and file size if you're going with avi.
Can you be more specific? Which mencoder option do you mean, exactly? I looked in `man mencoder` and there are lots of quantizer options How would you modify this line to set quantizer to 4 ?

CODE
mencoder `basename $1` -o $2 -oac mp3lame -lameopts abr:br=128 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1900:vpass=1

 

[todd]

I encoded a bunch of cartoons/movies to play back on the Pandora during a several-day car trip made in late December '08.... ooops.

Caillou's good. I really like the Scholastic videos, which generally are based on books that are then animated. Many are very nicely done, and many are done by a Canadian outfit ("Weston Woods" or something like that?). Also I like the (American, I assume) cartoon "Oswald." Good music, soothing, not overstimulating. Apparently they only made two DVDs' worth of those.

Re: resolution, I don't believe I'm hurting my kids eyes by using lower resolution. The Pandora's screen is tiny (relatively speaking) and I was intending the videos to be used in marginal situations (e.g., the back seat of a moving car where they both have to watch the same screen). I don't think the lower resolution will be very perceptible at all. I'm positive my kids won't care.

On my monitor at home, yes, I want good resolution. Hard disk space is cheap. For a screen that fits in my pocket and relies on pricey flash memory for storage? I'd rather have greater variety to keep them occupied than higher resolution for discerning eyes. My $0.02.

 

[clippa]

Yeah, on a small screen you could probably get away with halving the resolution. I'll probably do a couple of tests with bitrate and resolutions when I get my hands on andora1:
cosurgi, I've never really used mencoder, it seems unnecessarily complicated, I'm not sure which command you'd use, quant=4 or something? I use virtualdubmod for making avi's.
The reason for stretching the horizontal is just to preserve the vertical resolution so you won't lose any quality. You're probably right though, on a small screen, the quality loss will probably be unnoticeable and the encode will be quicker to just keep the horizontal and change the vertical to the desired aspect ratio.

I'm not comfortable with non-square pixels. Assuming that I watch the movie at good aspect ratio, it means that there's some horizontal scaling going on during playback. I prefer to just give a higher bitrate, it should be equivalent, shouldn't it?

Do you mean just encoding without resizing and then choosing the aspect ratio during playback? Yeah, that's fine, the results would be more or less the same and you'd have a smaller file but as you can't specify the aspect ratio in an avi file, if the video isn't just for you then you'll end up with people complaining that it's in the wrong aspect ratio. People usually have their players just set to "default aspect ratio".

I'm going to say "aspect ratio" one more time, for luck.

 

[.Gogeta§§J4BR.]

don't just shove rmvb down their throat, but no need for fullhd CABAC h264 either
cut the borders, resize it till its inside pandora's resolution, then make an xvid with a good bitrate and you shall have good space and quality
I have woody woodpecker here, with brazilian portuguese dubbing just for the memories

 

[timothee]

Thanks all for your answers and advice.

One reason I wanted to encode at full DVD res is that my DVDs are getting old and a little scratched. I figured I needed to make backup archives soon anyway, and I was hoping I wouldn't have to keep 2 copies: one full-res and one lower res for Pandora playback. I might consider downscaling just a bit to 624x480 (~88% of original 704x540) such that it can play on native resolution on the Pandora screen. For such cartoon, that's probably acceptable.

In any case, it looks like I'd better go for mp4 instead of x264 then. mp3 instead of ogg vorbis, I'll consider. I assume audio decoding accounts for less cpu than video decoding anyway (?). I'm also going to keep the mkv container and assume it will be supported by the Pandora. For dual audio setup, and using subtitles where available, mkv is what I prefer.

Cosurgi, thanx for your scripts, it's much appreciated. I had to write some specific scripts of my own to do these x264 Caillou DVD conversions. The DVD setups were a bit weird, you had to chose the language in a menu first. To manage that, the DVD contains duplicate video streams of all the episodes. For the english episodes, there are 2 audio streams per episode, one marked english, the other french, but both are in fact english. For the french episodes, each episode also contains 2 audio streams, one marked english, the other french, but both are in fact french. So to get one full episode, I ripped the french video stream plus one french audio track, then ripped the english audio, and finally merge them all into one mkv file. What a pain, and what a waste of DVD space! They could easily have fitted twice the number of episodes on one DVD without all this duplication!

 

[cosurgi]

Yeah, ripping DVDs in good language is another matter. Unfortunately it cannot be automated. That's how I do it (for polish language "pl"):

CODE

# to find the track you want, let's call it $NNN
lsdvd

# -v (verbose) shows the audio track for language "pl", this will
# be the -aid parameter, lets call it $AID

mplayer -v dvd://$NNN -ao none -vo none | grep pl


mencoder dvd://$NNN -aid $AID -oac copy -ovc copy -o filename_DVD_rip.avi

# for example $NNN is 4 and $AID is 131
mencoder dvd://4 -aid 131 -oac copy -ovc copy -o filename_DVD_rip.avi



The -oac copy -ovc copy are directly ripping into a file, without any encoding - so no data loss is going on.

 

[lulzfish]

I find Acidrip is very easy to use, it basically automates the scripts cosurgi has already posted and splatters a friendly GUI on top.

 

[TrevorBradley]

Ack! Now I have Caillou's whiny complain voice in my head! "BUT MOOOOOOOOOOOOOMMMMMMMMMY!!!!!" *shudders*

If we're going for Canadian content... Little Bear rocks... something like Neil Gaiman's imagination and wit with all the scariness removed..

I know, I've been there.. it's what the kids want to watch, not what the parents like...

Back to the original topic, I see no reason why Pandora shouldn't be able to handle this well, especially at 600kbps. I'd bet it could handle 1000kpbs, but best to check first.

You might learn something from various MythTV groups, who are used to 720x480 TV playback on low CPU machines. For instance:

http://www.mythtv.org/docs/mythtv-HOWTO-3.html

"A dual Celeron/450MHz is able to view a 480x480 MPEG-4/3300kbps file created on a different system with 30% CPU usage."

That sounds like you're *well* within limits.

 

[cbox]

I recommend SUPER for video resizing, it's basically a front end for mencoder but has all of the features and options and a batch mode which is handy for whole seasons of episodes.

 

[lulzfish]

All I can think of is the Youtube Poops featuring Caillou.

"What are we having for lunch today, mommy?"
"OWOWOWOWOWOWOWOWOWOWOWO"
"Yay!"

As for video, I seem to recall watching some Neon Genesis on my Pentium II. The versions I have are H.264 and MPEG4 AAC audio. The resolution is only 320 x 240, and it seems to be a combined bitrate of about 394 kbps. And it was almost watchable, too.

 

[notaz]

From what I've read, I'm not worried about codec/format support, but rather plain "can these files play smoothly on the Pandora?". I'm 90% sure they will play fine, but before I convert my whole collection, I've uploaded two of the episodes I have already ripped, in the hope someone could confirm they will play ok on the Pandora.

The mplayer I have is not fast enough to handle them unfortunately even when overclocked. I'm not sure if it uses NEON but I know it doesn't use the DSP.

 

[Mr.Gonzo]

I actually know the niece of the guy who draws the original books of Caillou (went to school with her)... she's one wild girl !
And yes i am Canadian.