mplex error in GUI for DVDAuthor

[TheManuel]

I have everything ready to go but the authoring process will not complete because of this error. Could it be I am running the max bit rate too high in the encoder (HC)?


(shrink and) mux video and audio files
INFO: [???] mplex version 2.0.0 (2.2.3 $Date: 2004/01/13 20:45:26 $)
INFO: [???] File D:\Viaje a PR - Disc 1.m2v looks like an MPEG Video stream.
INFO: [???] File D:\Viaje a PR - Disc 1 1.ac3 looks like an AC3 Audio stream.
INFO: [???] Video stream 0: profile 8 selected - ignoring non-standard options!
INFO: [???] Found 1 audio streams and 1 video streams
INFO: [???] Selecting dvdauthor DVD output profile
INFO: [???] Multiplexing video program stream!
INFO: [???] Scanning for header info: Video stream e0 (D:\Viaje a PR - Disc 1.m2v)
INFO: [???] VIDEO STREAM: e0
INFO: [???] Frame width : 720
INFO: [???] Frame height : 480
INFO: [???] Aspect ratio : 16:9 display
INFO: [???] Picture rate : 29.970 frames/sec
INFO: [???] Bit rate : 9500000 bits/sec
INFO: [???] Vbv buffer size : 229376 bytes
INFO: [???] CSPF : 0
INFO: [???] Scanning for header info: AC3 Audio stream 00 (D:\Viaje a PR - Disc 1 1.ac3)
INFO: [???] AC3 frame size = 1024

INFO: [???] AC3 AUDIO STREAM:
INFO: [???] Bit rate : 32768 bytes/sec (256 kbit/sec)
INFO: [???] Frequency : 48000 Hz
INFO: [???] SYSTEMS/PROGRAM stream:
INFO: [???] rough-guess multiplexed stream data rate : 9963496
INFO: [???] target data-rate specified : 10080000
INFO: [???] Setting specified specified data rate: 10080000
INFO: [???] Run-in Sectors = 89 Video delay = 13019 Audio delay = 0
INFO: [???] New sequence commences...
INFO: [???] Video e0: buf= 237568 frame=000000 sector=00000000
INFO: [???] Audio bd: buf= 16384 frame=000000 sector=00000000
++ WARN: [???] Stream e0: data will arrive too late sent(SCR)=312385097 required(DTS)=0
++ WARN: [???] Video e0: buf= 172634 frame=104020 sector=01772717
++ WARN: [???] Audio bd: buf= 13987 frame=108464 sector=00055093
INFO: [???] Scanned to end AU 125170
INFO: [???] STREAM bd completed @ frame 130516.
INFO: [???] STREAM e0 completed @ frame 125170.
INFO: [???] Multiplex completion at SCR=375880557.
INFO: [???] Video e0: buf= 3743 frame=125170 sector=02127410
INFO: [???] Audio bd: buf= 8192 frame=130516 sector=00066295
INFO: [???] VIDEO_STATISTICS: e0
INFO: [???] Video Stream length: 5841886 bytes
INFO: [???] Sequence headers: 6984
INFO: [???] Sequence ends : 1
INFO: [???] No. Pictures : 125170
INFO: [???] No. Groups : 6984
INFO: [???] No. I Frames : 6984 avg. size 67867 bytes
INFO: [???] No. P Frames : 34821 avg. size 54394 bytes
INFO: [???] No. B Frames : 83366 avg. size 23183 bytes
INFO: [???] Average bit-rate : 8237600 bits/sec
INFO: [???] Peak bit-rate : 9499600 bits/sec
INFO: [???] BUFFERING min 15 Buf max 235543
INFO: [???] AUDIO_STATISTICS: bd
INFO: [???] Audio stream length 133649408 bytes.
INFO: [???] Frames : 3659283367
INFO: [???] BUFFERING min 35 Buf max 14368
**ERROR: [???] MUX STATUS: Frame data under-runs detected!

Thanks

[Matthew]

I don't know the answer to your question, but for diagnostic processes it may be useful to attempt a mux using MuxMan and/or DVDPlanner.

[TheManuel]

I did it with Muxman and got an error along the lines:
"The buffer underflowed 6 times. Resulting DVD may not play smoothly"
Unfortunately, I had just downloaded it and ran it inside the zip file so I lost the log file.
Any ideas what the problem could be?

[Zeul]

Your max bitrate should be 9800 - the sum of the audio streams. So if your audio is AC3 448 kbps then the max video bitrate would be 9800 - 448 = 9352. Now it is perfectly normal for the encoder to allow the occasional spike above this max, as long as it doesn't last too long.

[TheManuel]

Your max bitrate should be 9800 - the sum of the audio streams. So if your audio is AC3 448 kbps then the max video bitrate would be 9800 - 448 = 9352. Now it is perfectly normal for the encoder to allow the occasional spike above this max, as long as it doesn't last too long.

Well, I don't exceed that bit-rate. If you look at the log file, the peak video bit-rate is 9499600 which divided by 1024 equals 9277kbit/sec. If you add my audio bit-rate of 256, the total is 9533, well below 9800. Besides isn't the limit 9.8Mbit/sec which multiplied by 1024 is actually 10035kb/sec?

I encoded a short, 10sec segment of the video at a very high bit-rate (exceeding 11Mb/sec) and it multiplexed without problems so I have not been able to narrow down the problem. Could it be the much longer original video allows more room for errors to occur?

My computer takes about 14 hours to encode the whole clip and this is why I have not simple gone trial and error to try to identify the problem.

[mpucoder]

The bitrates used in MPEG and DVD are not like memory sizes, 9800 Kbps means 9800000 bps

Although you may have set the max bitrate to 11Mbps, did the encoder actually achieve that bitrate?

The window for spikes is approximately 400ms, combined bitrates exceeding 9.8Mbps for longer than that will cause buffer underflow. What that means is the data for one or more pictures could not be placed into the player's buffer before it was needed by the decoder. Most modern players have buffers much larger than the model and can play the DVD without problems, but it technically is out-of-spec.

[TheManuel]

The bitrates used in MPEG and DVD are not like memory sizes, 9800 Kbps means 9800000 bps
.
Thanks for clearing that up. I guess I did exceed that in that case.


Although you may have set the max bitrate to 11Mbps, did the encoder actually achieve that bitrate?

The window for spikes is approximately 400ms, combined bitrates exceeding 9.8Mbps for longer than that will cause buffer underflow. What that means is the data for one or more pictures could not be placed into the player's buffer before it was needed by the decoder. Most modern players have buffers much larger than the model and can play the DVD without problems, but it technically is out-of-spec.
I am pretty the short test clips did achieve very high bitrates since the GFD log file reported a very hight peak rate but I don't know for how long it lasted. That might be the key. Perhaps the longer original video had some scenes with enough movement that the encoder maintained a sustained excessive bit-rate for more than the maximum allowable time window. Just my guess, of course.

[TheManuel]

Thanks for clearing that up. I guess I did exceed that in that case.

I take that back, I did a search on the web and 9800kb/s is the limit of video only. The total limit for video, audio and subtitiles is 10.08Mb/s so I am not exceeding it although I admit I am very close.

[mpucoder]

The 10.08Mbps figure includes all overhead (pack and packet headers, nav packs, filler packets), not just video/audio/subpictures. The total payload rate for all streams is 9800Kbps

[TheManuel]

The 10.08Mbps figure includes all overhead (pack and packet headers, nav packs, filler packets), not just video/audio/subpictures. The total payload rate for all streams is 9800Kbps

I reverse my previous reversal, then. I will re-encode the video so that my combined video and audio rate does not exceed 9800Kbps (it is a home video so it does not have any subtitles).

Thanks, mpucoder.
While we are on the multiplexing subject, can Muxman output mpg files instead of vob?

[mpucoder]

While we are on the multiplexing subject, can Muxman output mpg files instead of vob?No, the multiplex engine was written specifically for DVD. Adding options such as no NavPk, or specifying different mux rates, would most assuredly result in slower code. There are conceptual differences as well such as the VOBU, which is the basic multiplex unit for DVD and the heart of the process, and cells and vobs.

[TheManuel]

OK, mpucoder.
Thanks for all your comments on this.

[TheManuel]

I'm frustrated.
I finally replaced my defective CPU cooling fan so I re-encoded the video with HC to a lower bitrate and still I encountered the same error (log pasted below).
As you can see, the bitrate is legal by any standards so I don't know why the multiplexing is failing. I am running out of things to try and encoding the whole video in my computer takes about 14 to 15 hours.

Does anyone have any further suggestions?

Here is a summary of my source material:
- captured Hi8 home video at 720x480 29.97fps YUY2 with VirtualVCR to an avi file (audio at 48kHz)
- edited with Virtual Dub (did some cuts and pasted 1sec snippet of blue screen from the same footage in between some scenes to create transition; could the problem be there somehow?)
- video encoded to MPEG2 with HC to 8000 avg. bitrate, 9000max. bitrate, VBR bias 0, 18 2 GOP structure, interlaced video, alternate scan TFF, 10bit precision, best profile, mpeg quantization matrix
- audio encoded with Aften using BeLight to 384kb/sec CBR (tried ac3enc and got the same problem)
- authored with "Gui for DVDAuthor" which uses mplex to multiplex (tried with Muxman which also found underflows)

Gui for DVDAuthor log file:

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

d:\PR2006Disc1\Temp>Time: 11/7/2006 2:02:29 PM

(shrink and) mux video and audio files
INFO: [???] mplex version 2.0.0 (2.2.3 $Date: 2004/01/13 20:45:26 $)
INFO: [???] File D:\Viaje a PR - Disc 1.m2v looks like an MPEG Video stream.
INFO: [???] File D:\Viaje a PR - Disc 1_1.ac3 looks like an AC3 Audio stream.
INFO: [???] Video stream 0: profile 8 selected - ignoring non-standard options!
INFO: [???] Found 1 audio streams and 1 video streams
INFO: [???] Selecting dvdauthor DVD output profile
INFO: [???] Multiplexing video program stream!
INFO: [???] Scanning for header info: Video stream e0 (D:\Viaje a PR - Disc 1.m2v)
INFO: [???] VIDEO STREAM: e0
INFO: [???] Frame width : 720
INFO: [???] Frame height : 480
INFO: [???] Aspect ratio : 16:9 display
INFO: [???] Picture rate : 29.970 frames/sec
INFO: [???] Bit rate : 9000000 bits/sec
INFO: [???] Vbv buffer size : 229376 bytes
INFO: [???] CSPF : 0
INFO: [???] Scanning for header info: AC3 Audio stream 00 (D:\Viaje a PR - Disc 1_1.ac3)
INFO: [???] AC3 frame size = 1536

INFO: [???] AC3 AUDIO STREAM:
INFO: [???] Bit rate : 49152 bytes/sec (384 kbit/sec)
INFO: [???] Frequency : 48000 Hz
INFO: [???] SYSTEMS/PROGRAM stream:
INFO: [???] rough-guess multiplexed stream data rate : 9587000
INFO: [???] target data-rate specified : 10080000
INFO: [???] Setting specified specified data rate: 10080000
INFO: [???] Run-in Sectors = 89 Video delay = 13019 Audio delay = 0
INFO: [???] New sequence commences...
INFO: [???] Video e0: buf= 237568 frame=000000 sector=00000000
INFO: [???] Audio bd: buf= 16384 frame=000000 sector=00000000
++ WARN: [???] Stream e0: data will arrive too late sent(SCR)=312394166 required(DTS)=0
++ WARN: [???] Video e0: buf= 191709 frame=104023 sector=01718248
++ WARN: [???] Audio bd: buf= 14371 frame=108466 sector=00082641
INFO: [???] Scanned to end AU 125170
INFO: [???] STREAM e0 completed @ frame 125170.
INFO: [???] STREAM bd completed @ frame 144935.
INFO: [???] Multiplex completion at SCR=417403172.
INFO: [???] Video e0: buf= 237568 frame=125170 sector=02066032
INFO: [???] Audio bd: buf= 2560 frame=144935 sector=00110428
INFO: [???] VIDEO_STATISTICS: e0
INFO: [???] Video Stream length: 4176562508 bytes
INFO: [???] Sequence headers: 6984
INFO: [???] Sequence ends : 1
INFO: [???] No. Pictures : 125170
INFO: [???] No. Groups : 6984
INFO: [???] No. I Frames : 6984 avg. size 67031 bytes
INFO: [???] No. P Frames : 34821 avg. size 53203 bytes
INFO: [???] No. B Frames : 83366 avg. size 22261 bytes
INFO: [???] Average bit-rate : 8000000 bits/sec
INFO: [???] Peak bit-rate : 8999200 bits/sec
INFO: [???] BUFFERING min 15 Buf max 235543
INFO: [???] AUDIO_STATISTICS: bd
INFO: [???] Audio stream length 222621696 bytes.
INFO: [???] Frames : 3659297786
INFO: [???] BUFFERING min 67 Buf max 13891
**ERROR: [???] MUX STATUS: Frame data under-runs detected!

d:\PR2006Disc1\Temp>Time: 11/7/2006 2:19:38 PM

[Zeul]

Try encoding at 23.976 with GOp length of 12 and applying pulldown to the video stream. Or try reducing the GOP length to 15.

[TheManuel]

Thanks, Zeul.
I am re-encoding once again but this time I set HC to autogop to see if that works. I have my hopes high on this attempt. I will know tomorrow as it takes forever in my computer.

[TheManuel]

Finally got it work!!!

I just ran HC in autogop. If I had listened to HC's guide in the first place I would not have had all these problems. The thing is that I had read somewhere that NTSC had a standard GOP lenght of 18. Clearly my interpretation was wrong as this is simply the max permissible. Apparently there is a lot more to GOP's than it seems on the surface so it is better to let HC take care of that automatically.

Thanks again, Zeul!!!

[Zeul]

Glad you got it fixed.