RAmos RM400 PMP A/V sync difficulties.

[Graffiti Writer]

Hi everyone.

I bought a RAmos RM400 MP4 player, which is a great little device with an incredible screen, especially for the low price. Unlike a lot of eBay "MP4" players, this one does acutally use Xvid to compress the video, so a 2GB memory card goes a long way.

Trouble is, the video conversion software supplied (AVIConverter 3) is only in Chinese - I've figured it out, but haven't managed to find an English version yet. Anyway, when I use it to re-encode videos for the player (which only seems to accept them in the specifc format this converter uses) the audio quickly drifts out of sync. It starts off fine, and if you skip ahead a little (presumably to the next key frame) it's back on sync for a short while, then drifts off again. The audio goes out of sync whether I'm watching the videos on the player or in Media Player on the PC.

I've loaded the player's videos into VirtualDub (naturally!) and it does bring up the familiar warning about VBR audio in an avi file. But in the file information, VirtualDub is unable to recognise the audio compressor used. I think it might be Mpeg 1 Layer 2, but can't be sure. I've tried adding all kinds of different audio formats to the video, but the player won't accept any of them.

I've put a sample clip here (sorry it's 9MB, but I wanted to make sure it was long enough for you to see the problem): RAmos RM400 Sample Clip
and thought I'd ask you guys if you can analyse it and perhaps discover something about it where I have been unable, and recommend how I can combat this sync problem.

Also, I'd rather use VirtualDub to re-encode the videos for the player (once the sync problem's been sorted) rather than the bundled Chinese program, so if anyone can determine the specifics of the encoded sample clip so I can set up VirtualDub correctly, I'd really appreciate it (although the player uses Xvid, I think there's something a little different about the video encoding too, but it's beyond my very limited knowledge on this subject).

Thanks for all your help, guys! I appreciate anything you can do.

[hob_goblin]

I've got one of these too and had the same issues. have you solved this problem? Can you tell me how if you have? Has anyone else got some advice - I really need this player to work!

[Graffiti Writer]

No. I haven't made any progress with this yet. I'm still hoping someone on the forum with more know-how than me is taking a look at the sample clip and can offer some advice.

I'll make sure to keep this thread updated if I do make any progress, however.

[lylewinton]

Hi Graffiti Writer and all,

I've also just bought an MP4 player off ebay. Different model but had same problems with the conversion software AVIConverter 2.0. The problem seems to be that AVIConverter can't sync audio from a number of video formats including AVI and MPG files. If I convert from VOB files (DVD) it works perfectly.

So here is the solution I found. I use VirtualDubMod to convert from the orginal file to MKV format. Then use AVIConverter to convert from MKV to the MP4 player native AVI format (Xvid). The audio is now in sync for me.

[Soopafresh]

Looks like the audio is mp2. Here's a script to do the same as you were trying to do with Virtualdub - resamples and converts the audio to CBR. No promises, as I don't have one those players. If it works, great. Your source file won't be touched if it doesn't. The processed files will be named Fixed-oldfilename.avi


http://www.bestsharing.com/files/XAvLfGS227342/AVI_GAIN_MP2.zip.html


Place AVI files in the same folder as the unzipped files above. Doubleclick Avi_Gain_mp2.bat to run.

Make sure your source AVI file names do NOT have any spaces in them.

[pmpvictim]

I posted in https://forum.videohelp.com/viewtopic.php?p=1660056#1660056
Sounds like similar player. Program is called AVIconvertor. (but really its mencoder (XVid and MP2))
Audio gets madly far ahead of video yet demo.avi is 24fps, 596kbps and perfect!

[pmpvictim]

This also looks like mine:
http://www.mp4nation.com/products/index.php?PID=mp8276
Mine is 2G. The eBay site I bought it off seems now to be only doing a slightly more expensive 4G version

It seems I may have wrong version of mencoder supplied

The demo uses Version: Sherpya-MinGW-20060312-4.1.0 which I found now in download for AVIconvertor3.0

Is is possible these Rockchip only play at 20fps or 24fps?

I will experiment.

[pmpvictim]

If it is 24fps I may use DVDpatcher to pretend my source is 24fps, which is better than 25fps ->24fps conversion.

[pmpvictim]

OK I find that EVERYTHINg including the AVIconvertor that comes with the player does audio by frame aligned per frame interleave.

The demo.avi which is perfect sync has 50ms interleave, NOT video frame interleave (at 24fps this is like 1.2 video frames per audio frame).

Very odd. Now how to do this with mencoder Xvid /MP2 settings

[1eyepmp]

I have a similar MP4 Unit - the Teclast C260. It has 320x240 with Xvid support FM, Tetris, Mp3 etc...

The software provided is AVIConverter 3.0 - the gui to mencoder. For me , it produces working , low quality, AV synced but jerky video files.

I wanted to try using mencoder under Linux, mainly so that if it worked I could tweak it for quality - I find the complete lack of settings in AVIConverter annoying.

Thanks to finding this site, I have the correct settings for my player - it probably uses some Sigmatel chipset or something. (I now know to use MP2 for audio, not MP3).

With mine, I can achieve good AV sync at the expense of framedrops (jerky video timing) just by setting the output framerate to 22 fps (mencoder -ofps 22 ...)

Its O.K. to tweak the video bitrate up to 600, so already its better than AVIConverter
I did this because I noticed the name of the binary for AVIConverter had "22FPS" in it somewhere.

Everything I want so far comes in at 25 fps - I have had enormous trouble trying to get the audio to sync (I tried faking the incoming framerate with -fps 27.75) when converting. Video encoded with a speed of 25fps looks great - I can't get it to sync though.

I am experimenting with faking the audio sample rate - no luck yet, just women with beards. The player will only playback 44100 Hz, not 48000, os it needs some conversion anyway.

Ideally, I think I need something that will convert smoothly down to 22fps - I need to understand telecine and reverse telecine, I think.

This an example mencoder line I use for testing:

mencoder_320x240 -af volnorm -alang en -slang en -vf scale=320:-2,expand=320:240:0:0:1 -oac lavc -lavcopts acodec=mp2:abitrate=128 -ovc xvid -xvidencopts bitrate=600:max_bframes=0 -ass dvd://1 -dvd-device /shiva/Movies/Standard_isos/TIME_MACHINE_2002_D5A.iso -ss 00:19:00 -endpos 00:02:00 -o test2.avi -srate 44100 -ffourcc XVID -ofps 22

The binary has been hacked so I can place subtitles into the AVI cleanly, hence the filename.

Maybe the 22 fps will help.

[pmpvictim]

The AVIConvertor is just a GUI to mencoder using a text file convertor.ini

Each line of it is a command line for mencoder. You can change as much there as on Linux. I even changed the MP2 encoder to toolame.

I'm convinced that if I can achieve three things:
1) 25fps to 24fps (inverse pal to film, simply by change frame rate)
2) Resample audio from 48,000 for 25fps to 44,100 for 24fps (i.e. with 5% pitch change).
3) Interleave by 4086 bytes, not video frames.

Then my transcoded videos will be same as the supplied "demo.avi" which is perfect.

[pmpvictim]

If you have any supplied demo avi files that play perfect you need to analyse them and copy the frame rate, audio sample rate, codecs & settings and avi mux setting exactly. It doesn't however seem to worry so much about actual bitrate. 96 to 256kbps MP2 stereo audio plays OK. Mono appears to not work. At 24fps (but out of sync audio) 150kbps to 600kbps for video just changes the quality, doesn't seem to affect video or audio timing.

[1eyepmp]

I'm now happy with my MP4 player - I use linux mencoder to do it so I can batch things myself and I don't have to run windows.

The trick seems to be reducing general decoding overheads.
The audio is handled by hardware independently of the video - so it doesn't skip when the video cannot maintain framerate.

I think that's what's happening. For me, changing quality settings in the encoding makes all the difference to the resulting AV sync.

My Converter.ini for AVIConverter 3.0 looks like this:

[Version]
Ver=3.0

[Quality]
Quality-1=0
Quality0=Low\Normal\High

[Types]
Types-1=0
Types=320X240

[Scale]
Scale-1=1
Scale0=16:9\4:3\Full

[parameter]
1-1-1=-ofps 22 -vf-add scale=320:240 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=500:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=128
1-1-2=-ofps 22 -vf-add scale=320:240 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=500:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=128
1-1-3=-ofps 22 -vf-add scale=320:180 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=500:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=128

2-1-1=-ofps 22 -vf-add scale=320:240 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=400:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=64
2-1-2=-ofps 22 -vf-add scale=320:240 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=400:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=64
2-1-3=-ofps 22 -vf-add scale=320:180 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=400:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=64

3-1-1=-ofps 22 -vf-add scale=320:240 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=300:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=64
3-1-2=-ofps 22 -vf-add scale=320:240 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=300:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=64
3-1-3=-ofps 22 -vf-add scale=320:180 -vf-add expand=320:240:-1:-1:1 -srate 44100 -ovc xvid -xvidencopts bitrate=300:max_bframes=0:quant_type=h263:me_quality=4 -oac lavc -lavcopts acodec=mp2:abitrate=64

The thing I hated was the -ofps 22 - most of what I want to convert is at 25 fps, when I started by changing this, I lose AV sync in no time (audio ahead of video).

Now I have discovered that the combination of fps, audio bitrate, video bitrate and video quality need to be in a sweet spot, to keep that spot you must trade one for another.

When I use 25 fps, I have to use a video bitrate of around 450, no more. Audio must be no more than 128 and me_quality must be no higher than 4. That is a sweet spot - no AV desync.

So, I suspect you may have a dud player that just can't maintain the framerate even with very low settings.

Try setting me_quality to 3 - it will look uglier, but it might sync - that seems to make a big difference to the decoding time.

Good luck!

[pmpvictim]

Well I'll try some of these ideas, but the demo.avi has pefect sync and is 24fps and 596kbps video (though 96kbps audio).

I've tried those settings and it doesn't remotely work. The demo.avi has audio interleave every 4096 bytes, anything I build has either 40Kbyte audio interleave or video frame interleave.

[1eyepmp]

... Another thing that affects the overall sweet spot for encoding is the amount of screen you intend to use. I have found that using 25 fps, 450 Kb/s video, level 4 motion estimation and 128 Kb/s audio starts to have noticable desync after around 3-4 minutes of play for a film converted so that 1:1.178 fits all on the screen.

For an aspect ratio of 1:1.67 fitting all on the screen, a/v desync occurs in about 10 seconds.

I now use these settings, which give no desync for either of these film aspect ratios:

mencoder -af volnorm -alang en -slang en -vf scale=320:-2,expand=320:240:0:0:1 -oac lavc -lavcopts acodec=mp2:abitrate=96 -ovc xvid -xvidencopts bitrate=300:max_bframes=0:quant_type=h263:me_quality=4 -ass -ffourcc XVID -srate 44100

The artifacts are visible, but with a screen size of 2.4 inches, the motion is smooth and the a/v is in sync.

I don't know how the demo you have achieves such a high bitrate - maybe it uses very little of the screen ? I have a feeling it uses all of it, which leaves me questioning what its really capable of too.

The desync is odd because its not inherent to the AVI - when it falls out of sync, one can scan forward and then back and when it seeks to a keyframe, the a/v is in sync again until time wears it down and it slips again (with the above settings I can at least watch a whole film without this happening).
I played with re-assembling AVIs with lengthened sound - but when I realised I am only going to improve a play-through without any seeks, I stopped.

I have also noticed that sometimes the player will desync on a film it didn't desync on before - I just power cycle it and it works again.

I suspect it may have memory leaks in the code or something.

Your player is probably slightly different to mine, I hope some of what I have learned is useful - this thread helped me get it to where it is now.

[pmpvictim]

Demo is "full screen" 320x240" 24fps 496kbps Video Xvid. 96kbps MP2 "50ms" Interleave Audio (=4096 bit interleave I think), NOT video frame Interleaved.

Odd.

I haven't had time to look at it much more, maybe not time till later this week

[sere83]

sorry to hijack this thread, but I am experiencing a similar problem with my hacha video player (posted in another thread). i am trying to get it to play 24fps rather than 20fps. I just thought that maybe if i use the ramos version of aviconverter 3.0 then i could achieve the 24fps. Graffiti writer> any chance you could post a link to the ramos software so I could test it? if you could I would be unbelievably grateful.

[pmpvictim]

The is a UK website with the AVIconvertor 3. I'll also upload to my wiki site. www.wattystuff.net

[sere83]

thanx for the help. I asked some of the guys over at my www.mympxplayer.com too and I was told to get xilisoft video encoder, which I did. Using xilisoft I encoded some episodes of family guy @ 320X240 (24fps) 600kb data rate and 128kbps mp2 sound. These files play back perfectly on my hacha r280s (2.83" screen). I then tried to encode a dvd rip and hdtv entourage episode using the same settings. Both these files had A/V sync problems after about 1 or 2 minutes of playback. So I dropped the data rate to around 400kps on the entourage episode and it played back well (I think this could be boosted to about 425 as I tried at 450 and this played back almost perfect but did desync once and I had to scroll on a bit then it played fine for the rest) . I know the hacha has has a rockchip 240mhz processor and I think the ramos may be same (not sure?) I recomend trying some of the settings mentioned using xilisoft as I have had the best results here (even better than aviconverter 3.0). This would seem to correlate with what 1eyepmp was saying about the encoding 'sweet spot' on the telcast.

[pmpvictim]

I tried the xilisoft encoder (which is expensive) and it was identical out of sync to similar settings done with mencoder.
Odd.

[fritsg]

Sounds like the hardware looks a lot like the Ricatech RC 3300, ONDA VX858 or the QW MP-204. At least for me audio sync was problematic with mencoder but no problem with ffmpeg. All I used to convert videos was this:

ffmpeg -i input.avi -vcodec libxvid -r 20 -s 320x240 -b 300000 -acodec mp2 -ar 44100 -ab 128000 -vtag XVID output.avi

Hope it helps someone.

[freddyzdead]

The easiest solution to all this is to use viDrop, which has 3 presets for Rockchip players, and you can fiddle around as much as you like. http://skss.freehostia.com/go.php?http://learnfree.eu/vidrop/download/vidrop-0.54-install.msi
I would recommend adding the mplayer Windows Essentials codec pack to the program directory; then you can convert virtually anything.

I don't know why anybody needs such huge video bitrates for such a tiny screen; equally, why one would bother with high-quality audio, either. It's not Home Cinema, after all.

The info that was spread around that the Rockchip codec is based on XviD but not compatible with it is crap. The trouble with Rockchip is that it is intolerant of variations that other decoders take in stride. And it accepts only MP2 as audio.

I use 15 fps and ~90kbit video (2-pass) and 64kbit for the audio. This gives me a movie around 100 megs with some artifacts and a teeny bit jerky but quite watchable. I never have audio sync issues. I think those are mostly caused by taxing the decoding hardware beyond its modest limits. I would go lower than 64k for the audio, but the decoder won't accept it. Even so, I can put 30-40 movies in the 4 gig flash space.

Anyway, this arrangement is far superior to the AVConverter that came with it, or all the other ones I tried. I did find another version that was English, not Chinese, and made a hybrid of them. But, really, viDrop is the answer. And 2-pass encoding makes all the difference.

This is a good example of what can be done with AutoIT. People who use bloatware .net framework, C#, Java, etc., should take notice. The only reason the installer is so big is it includes mplayer and mencoder as well. Still, it's a lot smaller than similar packages. The EXE is only 427 kB and there are no top-heavy runtimes.
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