HD and transcoding issues with 6.2.10

[bialio]

I put the property above in last night - first thing this morning my wife was watching The Today Show and the first commercial break was Revenge of the Chipmunks

So nothing fixed on that front yet.

btl.

[waynedunham]

Originally Posted by bialio

I put the property above in last night - first thing this morning my wife was watching The Today Show and the first commercial break was Revenge of the Chipmunks

So nothing fixed on that front yet.

btl.

Dang, I just put that in my properties file but don't currently have any HD content to test it on. I was going to test it on some of tonights HD content.

I did notice something that probably relates as to why the problem happens. I have a Roku HD 1000 Photobridge and play my SageTV recordings over a shared network drive. They play great, with no Chipmunk, but I did notice that at the start/end of commercial segments just as they switch from HD to SD and back (most commercials are in SD) the Roku has a quick dropout of audio. Probably less than a second, but that's probably where the transcoder/MVP gets confused and messes up the audio stream.

On a side note, wouldn't you know it I finally get rid of the backlog of recordings to watch and the writer's go on strike. Oh well, time to watch all those episodes of old TV shows I've got archived.

[BFisher]

Originally Posted by bialio

I put the property above in last night - first thing this morning my wife was watching The Today Show and the first commercial break was Revenge of the Chipmunks

So nothing fixed on that front yet.

btl.

dang-gum! Wonder what's different with yours... my wife said she still hasn't seen an issue.

They play great, with no Chipmunk, but I did notice that at the start/end of commercial segments just as they switch from HD to SD and back (most commercials are in SD) the Roku has a quick dropout of audio. Probably less than a second, but that's probably where the transcoder/MVP gets confused and messes up the audio stream.

I noticed this too. In fact, we've noticed (prior to the fix I mention above) that CBS always seemed to work better than the other channels, and it appeared to be because our local news would have a promo before the show resumed. That promo always seemed to be in the same resolution, etc that would help things work properly.

The worst (a week ago) was Scrubs. It was like someone forgot to flip a switch in the show... it started off fine, and then all of a sudden the picture changed (just a little, but it was noticable) and the chipmunks appeared (and would not go away). I think I deleted that episode... too bad, I'd like to test it with this new setting to see if it worked properly.

[jvl711]

I have found a workaround for my issues. This will not help the people that are watching HD in realtime though.

I created transcode profiles for HD 16:9 and SD 4:3. Then I set the different transcode options for the appropriate channels.

To fix the chipmunk problem I transcoded the audio 2 MP3 instead of doing a pass-thru of the original stream. I have seen no chipmunk problems since doing that. I do not have 5.1 speakers on the TV that I am watching the shows on so I have no real loss in doing this.

[bialio]

That lends some validation to the theory that it's the switch from HD to SD (although it's really not SD - just pillar boxed 4:3 content) that triggers this. I'm guessing that the audio cutover from HD source (digital, possible DolbyDigital) to SD source (digitized analog audio) throws the transcoder for a loop.

btl.

[BFisher]

We had our first chipmunk last night (using the switch setting I posted above)... not bad after 3 days of continual use. And the chipmunk went away when I jumped forward and then backward. I can live with that until I get HD Extenders everywhere...

[jpwegas]

Originally Posted by BFisher

The worst (a week ago) was Scrubs. It was like someone forgot to flip a switch in the show... it started off fine, and then all of a sudden the picture changed (just a little, but it was noticable) and the chipmunks appeared (and would not go away). I think I deleted that episode... too bad, I'd like to test it with this new setting to see if it worked properly.

Originally Posted by jvl711

I have found a workaround for my issues. This will not help the people that are watching HD in realtime though.

I created transcode profiles for HD 16:9 and SD 4:3. Then I set the different transcode options for the appropriate channels.

To fix the chipmunk problem I transcoded the audio 2 MP3 instead of doing a pass-thru of the original stream. I have seen no chipmunk problems since doing that. I do not have 5.1 speakers on the TV that I am watching the shows on so I have no real loss in doing this.

Originally Posted by bialio

That lends some validation to the theory that it's the switch from HD to SD (although it's really not SD - just pillar boxed 4:3 content) that triggers this. I'm guessing that the audio cutover from HD source (digital, possible DolbyDigital) to SD source (digitized analog audio) throws the transcoder for a loop.

I've had the chipmunk problem for a while! Thanks for confirming it's not just me.

I also see this with Scrubs regularly, usually about halfway into the show.

bialio, I agree that the problem seems to be the audio formats switching midstream. It seems to always switch to chipmunk mode when coming back from a local station commercial (i.e. a news clip or something, which I assume is not AC3), to the network show (which I assume is AC3). So in my case what appears to be the AC3 -> non-AC3 switch is ok, but the non-AC3 -> AC3 switch triggers the problem.

Like jvl711, I have been converting my shows to MP2 audio and that seems to avoid the problem.

--John

[jpwegas]

Just curious, is anyone using the SPDIF output on the MVP (if theirs has one)? And if so, do you ever see the chipmunk problem?

If the problem is the audio decoder chip on the MVP getting confused, then using the SPDIF out might avoid the problem - since isn't the audio stream in that case basically just passed through?

--John

[Taddeusz]

Originally Posted by jpwegas

Just curious, is anyone using the SPDIF output on the MVP (if theirs has one)? And if so, do you ever see the chipmunk problem?

If the problem is the audio decoder chip on the MVP getting confused, then using the SPDIF out might avoid the problem - since isn't the audio stream in that case basically just passed through?

--John

I use SPDIF on my MVP and get the chipmunk problem.

[jpwegas]

Originally Posted by Taddeusz

I use SPDIF on my MVP and get the chipmunk problem.

Well shoot. I wonder what's causing the problem then.

--John

[Taddeusz]

I would guess that it's a break in the audio stream between the network feed and local ads that's causing the problem for the transcoder.

[malbec]

Have any of you tried the new beta to see if it kills the chipmunks?

[Taddeusz]

I haven't but I don't have any programs recorded off the station that creates chipmunks.

[mayamaniac]

What are your CPU speeds for smooth HD transcoding to the MVP on HIGH Quality setting?

On top of the chipmunk audio problem on some recordings, I get really bad stutters when the quality is set at High for the MVP. When set on Standard qulaity, it is smoother but the quality sucks, much worse than SD recordings.

My server is a Pentium 4 3.2ghz HT, and it stutters badly when transcoding HD to the MVP. I also tested it on a Core2Duo 1.8ghz system, and it also stutters. The strange thing is neither system's CPU spikes above 70% when transcoding. Its less than 50% CPU usage on the C2D system. So it's not like its making 100% use of the available processing power.

I just tested on a Q6600 2.4ghz Quad-Core system and the playback is smooth. I think quad-core is overkill so I'm wondering what CPU speed you guys are using to smoothly transcode HD to the MVP?

[BFisher]

I have a Quad-core I wanted no limitations and it's been working great. Worst I've ever seen is about 40% usage, and that was transcoding 2 HD shows to a MVP, playing an SD show, and a DVD, and recording 2 shows (which means 2 ShowAnalyzers running too). Great CPU

[hemicuda]

Grey's failed again the other night to compress. Changed the audio setting from AC3 to stereo and it went through to 100%. we'll see how it sounds when she fires it off later today. that one has had issues ever since i started recording it in HD.

Edit: w/ 2ch audio Grey's chirped after each commercial skip. annoying, but we got thru the whole thing w/o resorting to SD TiVo.

[Taddeusz]

Chipmunks are still there in 6.3.1. I had it happen last night when I was watching Men In Trees and Moonlight.

[jpwegas]

Originally Posted by mayamaniac

What are your CPU speeds for smooth HD transcoding to the MVP on HIGH Quality setting?

I'm pretty sure chipmunk problem is not CPU related, because:

If I convert a "chipmunk" recording to "DVD Standard with AC3" I get the same problem on the resulting non-HD recording (which doesn't require any transcoding).

If I convert a "chipmunk" recording to "DVD Standard" (i.e. MP2 audio), the chipmunks go away.

Side note: like hemicuda I sometimes get failed conversions when using the AC3 setting. No problems with MP2 stereo.

--John

[mayamaniac]

Originally Posted by jpwegas

I'm pretty sure chipmunk problem is not CPU related

Read my post again, the CPU question was for my stuttering problem when transcoding HD to the MVP. I'm planning to upgrade the CPU, but not sure what is the required speed. I know my P4 3.2Ghz and C2D 1.8ghz aren't powerful enough, I know my Quad-Core transcodes fine.

[mattdcknsn]

Originally Posted by mayamaniac

Read my post again, the CPU question was for my stuttering problem when transcoding HD to the MVP. I'm planning to upgrade the CPU, but not sure what is the required speed. I know my P4 3.2Ghz and C2D 1.8ghz aren't powerful enough, I know my Quad-Core transcodes fine.

Just to let you know from my personal experience, I have found that the Front Side Bus of the procs have more to do with transcoding than with actual horsepower. I had a 2.6 Intel with an FSB of 400 and it couldn't keep up. When I upgraded the procs to 3.4 and a FSB of 800 I am able to get standard quality. I havent had an oppurtunity to try out a higher FSB proc yet but nothing had changed on my system except that. When I was using the 2.6 procs my usage was around 60%, with the new procs it now hovers around 45%.

I think the quad core procs have 1333 FSB, so it might be worth it to look into.