DTS Audio drops out

[acpmadness]

Hey guys,

I've got a hand full of movies where the DTS audio drops out ruffly 30 times or so during a 2 hour movie. It only drops out for a sec and then it's fine again for a little while. I thought it might have been an issue where the PCH couldn't handle the movie. But now i'm thinking maybe it's not. Here is the specs of one of the movies where the audio drops out.

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 5 frames
Muxing mode : Container profile=Unknown@4.1
Codec ID : V_MPEG4/ISO/AVC
Duration : 2h 5mn
Bit rate : 11.9 Mbps
Nominal bit rate : 12.5 Mbps
Width : 1 920 pixels
Height : 800 pixels
Display aspect ratio : 2.400
Frame rate : 23.976 fps
Resolution : 24 bits
Colorimetry : 4:2:0
Scan type : Progressive
Bits/(Pixel*Frame) : 0.323
Title : ******
Writing library : x264 core 64 r983M b4b6483
Encoding settings : cabac=1 / ref=5 / deblock=1:-3:-3 / analyse=0x3:0x113 / me=umh / subme=6 / psy_rd=0.8:0.0 / brdo=1 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / chroma_qp_offset=-2 / threads=6 / nr=0 / decimate=1 / mbaff=0 / bframes=4 / b_pyramid=1 / b_adapt=2 / b_bias=0 / direct=1 / wpredb=1 / bime=1 / keyint=250 / keyint_min=25 / scenecut=40(pre) / rc=2pass / bitrate=12476 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / vbv_maxrate=50000 / vbv_bufsize=50000 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:0.70
Language : English

Audio
ID : 2
Format : DTS
Format/Info : Digital Theater Systems
Codec ID : A_DTS
Duration : 2h 6mn
Bit rate mode : Constant
Bit rate : 1 536 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz
Resolution : 24 bits
Language : English

Thanks for any help.

[chris57]

Make sure you have the latest firmware as there was a DTS dropout fix recently.

If it still dropouts to that extent then it is not the NMT as no one else has any issues anymore to that level. Try a different DTS file to see if its file related.

Could be first sign of network dropout if using SMB/NFS rather than http..

[acpmadness]

Thanks for replying.

01-17-090204-15-POP-403 (01.06.2009) is the lastest firmware right? I have it installed.

[chris57]

This has been looked at elsewhere the video bitrate is 50,000 vbr and so will exceed L4.1 spec plus bframes are >3.

[jj666]

Buy the movie and rip it yourself is always an option ;-)

-jj-

[acpmadness]

(07-02-2009 06:29 PM)chris57 Wrote:  This has been looked at elsewhere the video bitrate is 50,000 vbr and so will exceed L4.1 spec plus bframes are >3.

I've read this 10 times and I'm not sure what your saying.

Do you mean the PCH can handle a bitrate of 50,000 @L4.1?? Or do you mean the video I posted, the specs of it is to much for the PCH to handle?

Thanks.

[HeartWare]

The PCH is only guaranteed to handle files that are within the MPEG-4 Part 10 (AVC) Level 4.1 Main Profile specs (the same as any Blu-Ray player is limited by). If a file lies outside the specs for such an encode (such as the peak bitrate being 50+ Mbit), it's hit-and-miss as to whether or not the PCH can play it properly.

Blame it on the re-encode. Encode to proper specs, and the file should play fine. Fiddle with things you don't understand the consequence of, and you may run into problems...

See wikipedia: MPEG-4 and specifically Part 10 (AVC).

If a file is encoded with VBR at 50 Mbit, it means that the peak (maximum) bit rate will exceed this, and the MPEG-4 Part 10 Level 4.1 Main Profile only allows a maximum bit rate of 50 Mbit. Therefore any file with an average bit rate of 50 Mbit will exceed the maximum bit rate allowed by the MPEG-4 Part 10 Level 4.1 Main Profile.

Edit: Upon further examination, it appears that BluRay uses MPEG-4 Part 10 Level 4.1 High Profile and not Main. This profile allows up to 62½ Mbit peak bit rate, whereas Main only allows a peak of 50 Mbit.

[chris57]

Thanks for the detailed explanation of the bitrate issue. Aswell as bitrate b-frames are set to high for L4.1 profile.

This could either be a L5.1 encode whose header has been changed to L4.1 via the likes of H264info. Some people think for some reason that changing the header info will make the file play. It makes no difference as the problem is not reading the header and making a decision on whether or not to play based on header info. It is still attempted but the result is evident it makes no difference to playback.
Or simply the L4.1 parameters were not considered by the encoder, more likely.

[daniel_owen_uk]

It also states 5 reference frames, so even though it's header says 4.1, there is now way it can be a 4.1 encode, due to the settings being higher than 4.1 spec.

I think 50Mbps is within the spec of 4.1 but the rest of it isn't.

[acpmadness]

Thanks for the info guys.

Hope the C-200 will be able to play some of these video I have smooth.

[HeartWare]

Don't expect it to...

If the encode is beyond 4.1 specs, no NMT will have guaranteed playback, as all consumer-level chips to handle MPEG-4 decoding is limited to L4.1 (as this is the level used for BluRay).

There is absolutely no excuse for encoding files in levels beyond 4.1, as these levels are reserved for files that are to be used in environments waaaay beyond what a BluRay player can be asked to play back. Only ignorance or stupidity can be the cause for people doing this, and to expect that a consumer-level player should be able to play professional-level (for lack of proper term) encodes is unreasonable.

[acpmadness]

(07-04-2009 06:40 AM)HeartWare Wrote:  Only ignorance or stupidity can be the cause for people doing this, and to expect that a consumer-level player should be able to play professional-level (for lack of proper term) encodes is unreasonable.

Well the idea of encoding video's @L5.1 is you can get away with a lot smaller file. A L5.1 720p at a bitrate of 7 looks the same as a L4.1 at 30. When the quality is the same, what would you rather have on your hard drive... 6GB 720p file or 35GB 1080p file? I'm speaking of x264 encodes.

[SomeJoe7777]

(07-04-2009 04:09 PM)acpmadness Wrote:  Well the idea of encoding video's @L5.1 is you can get away with a lot smaller file. A L5.1 720p at a bitrate of 7 looks the same as a L4.1 at 30. When the quality is the same, what would you rather have on your hard drive... 6GB 720p file or 35GB 1080p file? I'm speaking of x264 encodes.

L5.1 does not save much. We're talking a few % maybe.

Properly encoded fully-compliant L4.1 files can have nearly zero artifacts at 6 Mbps @ 1280x720, or 12 Mbps @ 1920x1080 (This is what all my encodes are done as). This results in ~5 GB files for 720p, and ~10GB files for 1080p. (More if you do higher-end audio, e.g. DTS, DTA-MA, TrueHD).

You can go lower than that if the image is pillarboxed or letterboxed further. I have some 4:3 pillarboxed 1920x1080 stuff that looks flawless at 9 Mbps. Letterboxed 2.35:1 720p can go down to 5 Mbps. No need to change to funky resolutions, either, x264 is smart enough to not allocate hardly any bits to the black bars.

L5.1 encodes are a waste anyway, as they are not compliant with any consumer equipment.

As to the OPs file, I don't know who encoded that file, but those settings are way messed up. There are many things there that were changed/tweaked that shouldn't have been.

Psy-RD, IP/PB Ratios, etc. shouldn't be mucked with at all unless you're an x264 developer who deeply understands what those things do.