Stuttering


#1

I am trying to play some avi files from a network store. The avi play OK except that every 5 seconds or so the video pauses. The audio keeps playing OK but the video pauses for a second EVERY 5 seconds.

What could be causing this?   Both the linux box that is hosting the store and the WD TV live  are connected via a Gbit router. The avi files were generated by ripping a normal DVD and are about  3 gbyes in size. They play perfectly when I use a typical player.

Thanks,

-Andres


#2

Install MediaInfo (mediainfo.sourceforge.net) and run it against a file that has this issue.   Post the text output of it here.


#3

Thank you for your response

Thanks for mdeiainfo–a very useful tool

Here is the output:

General
Complete name                    : quantum_of_solace.avi
Format                           : AVI
Format/Info                      : Audio Video Interleave
Format profile                   : OpenDML
File size                        : 2.84 GiB
Duration                         : 1h 46mn
Overall bit rate                 : 3 830 Kbps
Writing application              : MEncoder 2:1.0~rc2-0ubuntu17+medibuntu1
Writing library                  : MPlayer
Original source form             : DVD ripped by acidrip.sf.net

Video
ID                               : 0
Format                           : MPEG-4 Visual
Format profile                   : Advanced Simple@L5
Format settings, BVOP            : Yes
Format settings, QPel            : No
Format settings, GMC             : No warppoints
Format settings, Matrix          : Default (MPEG)
Codec ID                         : XVID
Codec ID/Hint                    : XviD
Duration                         : 1h 46mn
Bit rate                         : 2 289 Kbps
Width                            : 720 pixels
Height                           : 480 pixels
Display aspect ratio             : 3:2
Frame rate                       : 29.970 fps
Standard                         : NTSC
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 0.221
Stream size                      : 1.70 GiB (60%)
Writing library                  : XviD 1.1.2 (UTC 2006-11-01)

Audio
Format                           : PCM
Format settings, Endianness      : Little
Format settings, Sign            : Unsigned
Codec ID                         : 1
Codec ID/Hint                    : Microsoft
Duration                         : 1h 46mn
Bit rate mode                    : Constant
Bit rate                         : 1 536 Kbps
Channel(s)                       : 2 channels
Sampling rate                    : 48.0 KHz
Bit depth                        : 16 bits
Stream size                      : 1.14 GiB (40%)
Interleave, duration             : 500 ms (14.98 video frames)
Interleave, preload duration     : 500 ms


#4

Boy, there’s sure a lot to hate about that file (Xvid, AVI container, etc).  As usual, I’d convert the original via Handbrake to an MKV file be done with all issues (High Profile preset).


#5

I did not know…I thought  that Xvid/Avi was considered good.  I will try Handbrake and the MKV container.

A related question.  Why do I even have to specify a video codec when I rip a DVD?   It seems to me that all players will play MPEG2 video and AC3 audio.  So why can’t the DVD ripper just rip the MPEG2 video and AC3 audio off the DVD and not do ANY transcoding?   

-Andres


#6

One thing I note about that is the VERY unusual framerate of 29.97 fps for a feature film.   

My copy of Quantum of Solace is 23.97 fps.

That could very well account for fast video / pause / fast video / pause while the audio catches up.  And the 1 second everyt 6 makes it even more likely because the ratio works out to 1:6!  

There are PLENTY of DVD rippers that do exactly what you describe.  DVDFab, for one.

Some people don’t want a rip that stays around 8 to 9 gigabytes, hence the rippers will also transcode and down-convert to make them smaller.


#7

Does a difference of a few frames per second really make that much of a difference?   I thought the WD TV Live could handle video at 60fps.

-Andres


#8

Your DVD ripper *shouldn’t* be re-encoding – I don’t know what you use so I can’t tell you, but AnyDVD (the gold standard) sure doesn’t).  And the resultant VOB files will play just fine with the Live (the only advantage to using Handbrake there is to reduce the file sizes without impacting quality).


#9

Opps, got in the middle of you two.

Yeah, there’s a WHOLE lot wrong with that rip (even if your ripper is re-encoding, it should NOT be messing with the frame rate).


#10

I am still confused.

You say that the ripper should NOT be messing with the frame rate. 

I thought the original DVD MPEG2 is at a frame rate of 29.970 fps.  So if this rip is at 29.97 fps then the ripper did NOT mess with the frame rate.  Instead you are saying that a frame rate of 29.97 is the reason why this file is not playing and that it should be 23.x fps so that it will play without studdering.   So are you saying that the ripper SHOULD mess with the frame rate (convert it from 29.x to 23.x)  in order for the file to play without studdering?

I am not trying to be combative here, I am just very confused by all of this DVD/video technology and I am trying to educate myself.  I really appreciate all of your help.

-Andres


#11

No, the original DVD is 23.97 fps, not 29.97

YOUR file is 29.97.  

Here’s the original log from re-encoding to MKV.  You’ll notice the frame rate is 23.97, and the aspect ratio is 16:9 (strict anamorphic original.)

[21:04:08] job configuration:

[21:04:08]  * source

[21:04:08]    + /temp/Quantum of Solace

[21:04:08]    + title 1, chapter(s) 1 to 29

[21:04:08]  * destination

[21:04:08]    + /movies/Pending/Quantum of Solace - 1.mkv

[21:04:08]    + container: Matroska (.mkv)

[21:04:08]      + chapter markers

[21:04:08]  * video track

[21:04:08]    + decoder: mpeg2

[21:04:08]      + bitrate 9800 kbps

[21:04:08]    + frame rate: same as source (around 23.976 fps)

[21:04:08]    + strict anamorphic

[21:04:08]      + modulus: 2

[21:04:08]      + storage dimensions: 720 * 480 -> 720 * 358, crop 58/64/0/0

[21:04:08]      + pixel aspect ratio: 853 / 720

[21:04:08]      + display dimensions: 853 * 358

[21:04:08]    + encoder: x264

[21:04:08]      + options: ref=2:bframes=2:subme=6:mixed-refs=0:weightb=0:8x8dct=0:trellis=0

[21:04:08]      + quality: 20.00 (RF)

[21:04:08]  * audio track 0

[21:04:08]    + decoder: English (AC3) (5.1 ch) (track 1, id 80bd)

[21:04:08]      + bitrate: 448 kbps, samplerate: 48000 Hz

[21:04:08]    + mixdown: Dolby Surround

[21:04:08]    + encoder: faac

[21:04:08]      + bitrate: 160 kbps, samplerate: 48000 Hz

[


#12

Yeah and just to add to what Tony is saying, about 99.9% of all movie DVDs are at a frame rate of 23.97.  It would be very odd indeed if otherwise (television “movies” are a different beast, as some of them are even interlaced).

Use a quality ripper like AnyDVD and you’ll be much better off.


#13

OK, I see, my mistake.


#14

Well, I ripped a DVD using HandBrake and everything is working just fine now.  Thanks guys for all of your help.

HandBrake is really very nice–I think I like it.

-Andres