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Xvid playback problems COBY TF-DVD7377
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briz3141
Newbie
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6. June 2008 @ 19:24 |
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Hi
I just recently purchased the COBY TF-DVD7377 , and have tried five different xvid's, and neither one of them plays correctly. There is a lot of blocky/jerky motion to the vidoes when played on the COBY. I have tried the same xvids on a Medion portable 20GB player that is almost three years old and they played fine on that, they also play fine on my PC.
What i have tried: packing with MPEG4 Modifier, removing the user data, changing aspect ratios etc..all with no effect, the file still plays back jerky and blocky. The below is a snapshot from mpeg4modifier of the original file:
Packed bitstream: No
QPel: No
GMC: No
Interlaced: No
Aspect ratio: Square pixels
Quant type: H.263
FourCC: DX50
User data: XviD0037
I-VOPs: 1328 (0.79%)
P-VOPs: 62397 (36.94%)
B-VOPs: 105208 (62.28%)
S-VOPs: 0 (0.00%)
N-VOPs: 0 (0.00%)
Max consecutive B-VOPs: 2
1 consec: 25.61%
2 consec: 74.39%
Here is a snapshot of a file that works correctly, this is a DivX file that i found on the 100fps.com site
Packed bitstream: Yes
QPel: No
GMC: Yes (2 warp points)
Interlaced: No
Aspect ratio: Square pixels
Quant type: H.263
FourCC: DX50
User data: DivX501b450p
I-VOPs: 18 (2.14%)
P-VOPs: 286 (34.01%)
B-VOPs: 403 (47.92%)
S-VOPs: 134 (15.93%)
N-VOPs: 0 (0.00%)
Max consecutive B-VOPs: 1
Warp points used:
1: 100.00%
As i said above by packing the file it has no effect, nor does changing the user data to DivX501b450p, although i don't know whether that is a tag or actually refers to some specific codec that is greatly different to xvid0037. Also i notice that the working divx has S-VOP's and Max consecutive B-VOP's of 1 as compared to 2 in the file that doesn't play correctly. Does anyone know what is going on or how i could fix this easily without having to re-encode ? I'm new to this as of about an hour or so ago, and am really googled out trying to find info on this, so i thought there might be a kind sould out there on this board who could help with this mystery. I have also tried contacting COBY support several times as well as leaving an email, and nothing. btw, great little unit for just over $80 that i paid, just wish this little xvid problem wasnt there.
thanks
b/
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briz3141
Newbie
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6. June 2008 @ 21:44 |
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... just to follow up from my own post, i notice that the problem file in the previous post has a fps of 23.976 according to GSpot whereas the smooth file has a fps of 50. I wonder if this low frame rate could be the problem and whether re-encoding to 29.970 would fix it?...
... just had another look, and i dont think its the fps,... will have another look later.
This message has been edited since posting. Last time this message was edited on 7. June 2008 @ 19:38
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carpie
Newbie
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10. August 2008 @ 03:34 |
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I don't know if you've found your problem yet, but I also have this DVD player and have had problems for months, though not the same as yours. However, your tip about grabbing a working DivX file off 100fps.com was the idea that allowed me to solve my issues. Thanks!
Again I don't know if this will help you directly, but I will explain my problems and their resolution. Maybe it'll help you, and hopefully it'll help anyone else with the player and similar issues.
First a little background. I encode my videos in Linux, but the tools I use can be used on other platforms. Most of my source files are MPEG2 videos from my MythTV box. The MPEG2 files played fine on the Coby. However, I was having two issues with MPEG4/DivX playback. My MPEG4 files were in AVI containers.
1) I would get no video, but the audio would play fine. The screen would just sit there and show the file tree. The AVI files have identifiers in them called 'fourcc'. I was using FMP4 and XVID. The player apparently didn't like them, so I forced them to DX50 when I encoded. Here are two ways to do this without re-encoding:
mencoder -ffourcc DX50 -oac copy -ovc copy -o outfile infile
or
ffmpeg -i infile -acodec copy -vcodec copy -vtag DX50 outfile
After doing this, the video showed up but then came the second problem:
2) The video plays as if it were in fast-forward mode and the audio plays about 3 to 5 seconds and stops. The video continues in fast forward mode. After analyzing the 100fps.com good video and my videos, I was able to determine that the audio in the good video was encoded with a constant bitrate while mine was encoded with a variable bitrate. I changed my audio to a constant bitrate and the videos played correctly! I was unable to force ffmpeg to create constant bitrate audio, but here's how to convert an existing video to CBR with mencoder:
mencoder -ovc copy -oac mp3lame -lameopts cbr:br=128 -o outfile infile
You can check to see if your audio is CBR or VBR with tcprobe which is part of the transcode package.
tcprobe -i video.avi
This will report CBR or VBR.
I haven't noticed any stepping or jerky video. However, I was playing around with low (video) bitrate clips while trying to get this to work. I haven't done enough experimentation to determine how high of a bitrate this player can handle...
Good luck. I hope this helps...
This message has been edited since posting. Last time this message was edited on 10. August 2008 @ 03:37
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briz3141
Newbie
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10. August 2008 @ 19:15 |
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I'm glad you solved your problem! I did get some of my divx's working , but that was by re-encoding the whole video again, not just the audio. I used virtualdub for this step, although at one point i tried ffmpeg but had no luck, even when i tried changing the fourcc values, but i may give it another go with the method you mentioned. Thanks heaps!
Another thing i tried doing was getting a youtube video and converting it to divx, but if i recall i was using ffmpeg and the result on the Coby was very fast video playback and way out of sync audio obviously!
Perhaps i will give this another go as well, have you ever tried converting a youtube video ?
Any reason why you chose mencoder over ffmpeg? There not so easy to use first time, wish the docs were a little better, but hey, its free! ;)
Thanks for the reply, didnt think this would ever get one! :)
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carpie
Newbie
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11. August 2008 @ 00:17 |
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I have not tried converting youtube videos, but the symptoms sound very much like my second problem. If you still have one of those around try the mencoder cbr thing and see if that helps.
I prefer to use ffmpeg as, to me, the options seem more logical and are easier to remember. For example, here's the line I typically use to convert my MythTV mpeg-2 encoded recordings:
ffmpeg -i infile -async 1 -acodec mp3 -ab 128k -vcodec mpeg4 -qscale 4 -deinterlace outfile
This is fairly readable: Load the input file, do some audio sync magic while converting the audio to 128kbps mp3 and convert the video to mpeg4 variable bit rate with a quality factor of 4, deinterlace it and write it to outfile.
Now consider the rough equivalent in mencoder:
mencoder infile -oac libmp3lame -lameopts br=128 -ovc lavc -lavcopts vcodec=mpeg4:vhq:vqscale=4 -vf pp=fd -o outfile
Does the same thing (I think) but not as clear to me...
As to why I choose to use mencoder in this case, it was because I couldn't force ffmpeg to make the audio constant bitrate (if anyone knows how, feel free to enlighten me!) I was able to add cbr:br=128 to the mencoder audio section to get a constant bitrate.
I think the mencoder document at the mplayer website is full of good info and the documentation is great -- if you're a video formats expert. It seems like there is a ton of flexibility there. I'm not an expert so I've come across my magic set of steps through late-night googling and a whole lot of trial and error. If it helps you give it another go, here is my magical set ;)
I edit my video clips (if need be) with avidemux. The resulting file is mpeg-2 video and mp2 audio in an AVI container. I then run:
mencoder -forceidx -oac copy -ovc copy -o outfile infile
This rebuilds the AVI index and seems to help me avoid the dreaded audio sync issues when I re-encode the video. Next, I do the conversion to mpeg 4 (infile is the output of the previous mencoder invocation):
ffmpeg -i infile -async 1 -acodec mp3 -ab 128k -vcodec mpeg4 -qscale 4 -deinterlace -vtag DX50 outfile
Again, the magical async flag combined with index rebuild I did before has made my audio sync problems go away. Normally, I'm done here and store these files on MythTV videos harddrive. However, if I want to make these compatible with the COBY, I add the following step (again infile is the outfile of the previous step):
mencoder -ovc copy -oac mp3lame -lameopts cbr:br=128 -o final_outfile infile
Finally I have a COBY compatible mpeg4 file!
Now granted, I could have probably eliminated a step by using mencoder to do the video conversion and going straight to CBR audio, but sometimes I do this by hand and it's easier to remember the ffmpeg bits. Also, this magic set of steps has produced quality videos for me after much trial and error (mostly audio sync issues) and I'm reluctant to do anything different ;)
Good luck! I hope you're able to get all your videos working!
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