[PROBLEM] Playback speed of 1080p dts movie is slowing down

[Smieh]

hi there,

got a little problem here with my pi + xbian.

Software
XBian version: 1.0 beta 2
XBMC version: 12.2 (the standard version that comes with beta 2)
Overclock settings: default

Hardware
Power supply rating: 2A
RPi model (model A/B 256mb/512mb): B / 512
SD card size and make/type: SanDisk 8GB microSDHC
Network (wireless or LAN): LAN (100MBit)
Connected devices (TV, USB, network storage, etc.): Audio Receiver via HDMI (DTS / DTSHD capable), LAN

Problem description:
Got the following 2 files:


Both files are located on the same NAS connected to xbian via SMB.

The first one (located on top) plays fine without any problems.
The second one plays well for the first 2-3 minutes but after that time - something strange happens. It seems like xbmc is reducing the playback speed of the movie - it runs without any drops or stuttering but only at about half the speed (if you don't know what i mean - open a video file in vlc on your desktop an reduce the playback speed to 0.5x).

The only difference i see is the different overall bitrate (11 vs. 23 Mbps) - had the same problems with another file which was also equal to the 2 files from the screenshot but had an overall bitrate of 16 Mbps. If i convert DTS to AC3 5.1 the 23Mbps and the 16Mbps file work fine.

Any ideas?
Is there a possibility to check the connection speed between my nas and the pi? (i assume that maybe the 23Mbps is just too much data although that shouldn't be a problem for a 100MBit network...)

[IriDium]

This could be one of two things.

You don't mention what NAS you have - but I would check that it is not maxing the CPU or I/O.

Have you checked the box in XBMC to use DTS receiver?

[Skywatch]

Can you monitor your nas via ssh or http and see the cpu and memory usage. It might be a memory buffer issue where the buffer is being filled faster with the larger file? - Just a thought!

Skywatch

[Smieh]

(7th Jan, 2014 12:03 AM)IriDium Wrote:  This could be one of two things.

You don't mention what NAS you have - but I would check that it is not maxing the CPU or I/O.

it's a self-built NAS - dual core celeron with 2.6GHz, 8gb ram. cpu usage is around 2-4% during playback, ram usage around 2.2gb, network speed around 18-25MBit. Network speed doesn't slow down during the time the video is playing slower...

(7th Jan, 2014 12:03 AM)IriDium Wrote:  Have you checked the box in XBMC to use DTS receiver?

it is checked and the av receiver is displaying dts which means it is receiving a dts track...

i played this file:


and recorded a movie of the xbmc status infos on screen. slower playback starts around 35 seconds - there are also some drops this time - haven't been there last time i played this mkv file.

Video:
http://smieh.org/stuff/video.mkv

don't know what to do maybe it's just too much bitrate to handle?

[mk01]

@Smieh

the same problem is with both audio tracks ?

[rikardo1979]

1st you dont need to post the MediaInfo screenshots as there is an option to out all the info as a text and than just add it here and tag as code
2nd I recognize this video file you posted a sample of and we have discussed the same file not long ago somewhere here and it seems to be the file issue.its coded the way that RPi dont like/handle. not sure where is that thread but I would say just reencode the file would be the easiest way

[Smieh]

@mk01
yeah - same problem with both audio tracks. with the second one (english) it's even worse...

@rikardo1979
i think i found that thread - but when i'm looking at the mediainfo output for file 1 (which plays without any troubles) and compare it to the mediainfo of file 2 then there is not really a difference...

Code:

General
Complete name                            : File 1
Format                                   : Matroska
Format version                           : Version 2
File size                                : 11.0 GiB
Duration                                 : 2h 16mn
Overall bit rate mode                    : Variable
Overall bit rate                         : 11.6 Mbps
Encoded date                             : UTC 2011-09-16 09:33:03
Writing application                      : mkvmerge v4.9.1 ('Ich will') gebaut am Jul 11 2011 23:53:15
Writing library                          : libebml v1.2.1 + libmatroska v1.1.1
Attachment                               : Yes

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 5 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 2h 16mn
Width                                    : 1 920 pixels
Height                                   : 816 pixels
Display aspect ratio                     : 2.35:1
Frame rate mode                          : Constant
Frame rate                               : 23.976 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Title                                    : File 1
Writing library                          : x264 core 116 r2074 2641b9e
Encoding settings                        : cabac=1 / ref=5 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=18.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language                                 : German
Default                                  : Yes
Forced                                   : No

Audio #1
ID                                       : 2
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Format profile                           : MA / Core
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 2h 16mn
Bit rate mode                            : Variable
Bit rate                                 : Unknown / 1 509 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossless / Lossy
Title                                    : Deutsch DTS-HD-MA 5.1 @ 4312Kbps
Language                                 : German
Default                                  : Yes
Forced                                   : No

Audio #2
ID                                       : 3
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Format profile                           : ES
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 2h 16mn
Bit rate mode                            : Constant
Bit rate                                 : 768 Kbps
Channel(s)                               : 7 channels / 6 channels
Channel positions                        : Front: L C R, Side: L R, Back: C, LFE / Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossy
Stream size                              : 748 MiB (7%)
Title                                    : Englisch DTS-ES 6.1 @ 768Kbps
Language                                 : English
Default                                  : No
Forced                                   : No

-----------------------------------------------------------------------------------------------------------------------------------------

Code:

General
Complete name                            : File 2
Format                                   : Matroska
Format version                           : Version 2
File size                                : 17.4 GiB
Duration                                 : 2h 4mn
Overall bit rate mode                    : Variable
Overall bit rate                         : 20.0 Mbps
Encoded date                             : UTC 2011-09-17 20:40:55
Writing application                      : mkvmerge v4.9.1 ('Ich will') gebaut am Jul 11 2011 23:53:15
Writing library                          : libebml v1.2.1 + libmatroska v1.1.1
Attachment                               : Yes

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 5 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 2h 4mn
Width                                    : 1 920 pixels
Height                                   : 816 pixels
Display aspect ratio                     : 2.35:1
Frame rate mode                          : Constant
Frame rate                               : 23.976 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Title                                    : File 2
Writing library                          : x264 core 116 r2074 2641b9e
Encoding settings                        : cabac=1 / ref=5 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=17.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language                                 : German
Default                                  : Yes
Forced                                   : No

Audio #1
ID                                       : 2
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Format profile                           : MA / Core
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 2h 4mn
Bit rate mode                            : Variable
Bit rate                                 : Unknown / 1 509 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossless / Lossy
Title                                    : Deutsch DTS-HD-MA 5.1 @ 3743Kbps
Language                                 : German
Default                                  : Yes
Forced                                   : No

Audio #2
ID                                       : 3
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Format profile                           : ES
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 2h 4mn
Bit rate mode                            : Constant
Bit rate                                 : 768 Kbps
Channel(s)                               : 7 channels / 6 channels
Channel positions                        : Front: L C R, Side: L R, Back: C, LFE / Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossy
Stream size                              : 685 MiB (4%)
Title                                    : English DTS-ES  6.1 @ 768 kbps
Language                                 : English
Default                                  : No
Forced                                   : No

would be nice to know the reason why it's not playing well. is there anything i can do to figure out why there is this strange problem?

[rikardo1979]

this is one of the strange thing on RPi and I cant really say why, but its not a 1st time we have seen this.
There is a guy called @popcornmix or @Dom (same person) on XBMC or RPi forum. I would suggest try to locate his threads about this or contact him direct for more (not saying he would be able to help) or just try to simple re-encode this file

[mk01]

@Smish,

can you grab latest firmware and xbmc? I pushed today to stable repo. fw should be ending .11 and xbmc .18 (deb pkg versions).

[Smieh]

@rikardo1979
i already converted the audio track from dts to ac3 days ago - the file works without any troubles / lags / drops. but i'd like to help finding the reason for this strange behavior...

@mk01
will try that tomorrow in the evening and post the results here...

[freem@n]

(8th Jan, 2014 10:47 AM)mk01 Wrote:  @Smish,

can you grab latest firmware and xbmc? I pushed today to stable repo. fw should be ending .11 and xbmc .18 (deb pkg versions).

is updating the fw in XBian as simple as doing sudo apt-get upgrade? or is there some sort of special command to do this?

[mk01]

yes, that simple.

---

or use xbian-config GUI in xbmc