Audio 'popping' converting from DTS to AC3

[THRobinson]

Have some files that are simply too big for my server, and frankly, movies that I don't need to have that big a file for.

So, been using VidCoder (Handbrake, same thing but I like it better) to convert with and for the most part it's been working great however, I've noticed lately that the audio about half the time, seems to have spots where the audio cuts in/out, that sorta static popping sound.

I'm changing the DTS 5.1 down to AC3 5.1, bitrate 640, sample rate same as source, no gain changes.

Not sure what's happening... I'll reencode the video to MP4 at around 4,000kbps, 2-pass, high priority, medium speed, same as source FPS... I know, constant quality is "better" but I don't have the time to reencode a movie 2-3x at 9h a conversion to get the size down where I want. Video quality wise I am very happy with the results so, not an issue.

Basically... just trying to figure out why the audio is coming out crappy. Should I use AAC? Different settings? I don't recall having these issue before, but then again, maybe I did and just now noticing it.

[Baldrick]

Maybe just try something else ripbot264 and see how it sounds.

Or use popcorn mkv audioconverter just to change the audio to ac3 and see how it sounds. Then just copy the audio in vidcoder.

[THRobinson]

I'll give that a try... usually I end up using MKVMerge and remuxing what I just did with audio from another source. Works, but, then I lose the MP4 which isn't a big deal I suppose, but, still, rather be able to just hit convert and have it done properly all at once.

Does anyone else have issues with converting to AC3 from DTS? Could it be a case where I need new codecs? or something along those lines?

[Baldrick]

HandBrake / vidcoder doesn't use any external codecs so nope.

[THRobinson]

Hmm... what else could it be then. I can't be the only person converting down DTS to AC3 using this app. :S

Have to try the other software when I get home and well, when I have something to convert.

Drives me nuts, because I usually discover the problem after the source file is deleted. It's tricky to find because not always throughout the entire video, often its for a few seconds then gone, and maybe comes back again later.

One of those issues that's gonna be a pain figuring out I know.

[Baldrick]

Have you tried play the video with ac3 with several players? VLC, MPCHC, etc?

[THRobinson]

No, not yet, will try that though... Just tried Windows Media Player... same glitches.

I use XBMC (I guess KODI now) as a media centre, which is what I always use... I do have a K-Lite Codec pack installed, which doesn't affect XBMC but, does for WMP, which didn't seem to make a difference.

[_Al_]

I don't recall having these issue before, but then again, maybe I did and just now noticing it.

Have you tried different PC or with different player, or phone whatever? Just to eliminate, if there is a problem with your your PC.

[THRobinson]

So, I ran a little experiment yesterday...

I used Popcorn to convert to AC3 5.1 @640kbps and kept the original DTS file.

I then ran VidCoder and

1 - Did a passthrough for the Popcorn coverted AC3 file
2 - Added a track that was the DTS file converted to AC3
3 - Added a track that was the DTS file converted to AAC Pro Logic II

The Popcorn file... no issues, sounds great.

The two files converted from DTS with VidCoder were both garbage. Not sure why... never an issue before... maybe it's the source file and VidCoder doesn't like how it was made? or just VidCoder not doing a good job the past few releases?

Kind of a pain to do the extra step though... I'll basically have to use Popcorn to convert the audio file, then use VidCoder to re-encode the video with the audio set to passthrough. Not the end of the world but, would be nice to figure out why it's being a pain.

[RappinRod]

Hello: VidCoder has been my encoder of choice since it came out..I cant remember the last time I had a problem converting Dts to Ac3 at 640kbs for 5.1 channel.I use 0 gain and 0 drc..I convert all the 720p and 1080p hd video files to Mkv H.264(x264)1024x576 at 3689 avg bitrate,variable framerate super fast preset,tune to film,high profile,level 4.1..I also mux in or hardcode subtitles flawlessly.I would keep the dts sound But I have a few 1st generation Western Digital media players around my home and they do not passthrough dts audio..In my opinion I cant tell much difference between the dts and ac3 sound and the files are smaller converting to ac3 640kbs for 5.1 surround..VidCoder uses all 8 cores of my processor and turns a 720p 4.3 gig file into a 2.6 gig file in about 9 minutes and and 11 minutes for a 1080p file conversion.I honestly cant see of a difference between my 576p 16/9 aspect ratio encodes vs the downloaded 720p or 1080p files on any of my led TVs up to 55 inches.Baldrick made a point earlier in his post,,try installing Lite Alloy (my player of choice) or Mpc-hc video players.I also downloaded madvr video renderer if you want,which does wonders viewing these types of files with these two video players.And download the newest Beta 2.1.0 VidCoder from their websight under the downloads tab..VidCoder will error out right away if there is something wrong with the original dts file but its rare in this day and age..One other thing I use the built in x265 encoder and getting between 85 and 110 fps using the default quality setting about (18min for an hour and half of video) encoding speed and the finished product is off the wall quality at 1024x576 with ac3 sound and about a 900 megabytes in size..Dont give up on VidCoder its a great superfast user friendly encoder..Good luck and change your computers video players...~

[THRobinson]

I tried using Handbrake, most current version, and tried converting again with the same issue.

I've used VidCoder for 2yrs without issue, but recently it's been hit/miss with DTS. Sometimes it seems fine, sometimes it obviously got a problem.

So, grabbed Handbrake as per the suggestion at the VidCoder forum to see if the same issue, and ya, same thing.

I have a Core2Quad Q9450 with 3GB ram, converting 1080p at medium speed takes about 6-8 hours. I start it and go to bed, that way the computer isn't in use by anything except VidCoder. I don't think my computer hardware would be the problem, a good quad core and 3GB ram should be enough to convert audio. The video has no issues.

Tried Windows Media Player as another player.

Didn't try another computer... the converted AC3 file from DTS using Popcorn works fine, and the the original DTS is fine as well. Didn't see a point in trying another computer at that point. Computer can play DTS and ACS just fine, just not AC3 created through Handbrake/VidCoder.

[RappinRod]

Hello: Did you try going into the audio settings on your video player and make sure its set to system default,,if not try that,,if that dosent work try any other sound device in the dropdown list of the player your using..I dont know why but if I recall a few times in the past my players default sound device sometimes was changed if I added an audio card and or made some audio software changes that sometimes reeked havoc in my video players audio properties..Windows Media player is subpar compared to other players out there in my opinion..And you should give my settings a try in VidCoder you might be pleasently surprised at the results..Anyway good luck with whatever you do...~

[THRobinson]

Shouldn't matter.... DTS converted to AC3 using Popcorn played fine, DTS converted to AC3 using VidCoder/Handbrake didn't.

Windows Media Player is using my system sound card and PC speakers, and XBMC Media Player is using the HDMI audio through my TV.

If it was the player or system, I would suspect that both converted AC3 files would sound bad, not just what was converted by VidCoder and Handbrake.

Totally stumped... again, never an issue before, and not always an issue now. I did try the same source file 3x and had issues all 3x... which is why I'm wondering if some DTS files are different than others? Like different codecs used to make them? In which case maybe the problem is just simply that VidCoder/Handbrake dislike some source files and not others.

[RappinRod]

Hello Again: I just encoded ten 720p and three 1080p files today,eight with flac or dts 1500kbs audio to 576p with ac3 5.1 640kbs audio the rest were just audio passthrough,,I also did half those files x265 with dts to ac3 all without a problem and NO popping using VidCoder 2.1.0.0 beta..It may be your settings or that something has changed recently in your system.You said this problem just started happening not too long ago.Try Uninstalling VidCoder and purge it completely from your system,then try using the newest beta portable..This is just a shot in the dark but maybe you could try a system restore and see what happens,,you can always undo it..These are things I would try to do before using Popcorn,Eac3to,Aften,Mkv2ac3 but that may be your only recourse until you can find the glich,thankfully it dosent take long at all for the extra step or you can try ShanaEncoder 2.10.1 its alot like VidCoder but dosent use a modified Handbrake to encode,it handles dts to ac3 very well and it is just as fast or faster with the same quality output.I dont use it much because it only hardcodes subtitles (dosent mux) if needed and it hasnt been updated since december2014..Good luck

[Fortissimo]

For what it's worth, I have the exact same problem here. I start with a 10GB MKV and convert it down to a 5GB MP4, a process I've done countless times. But in one that has a DTS audio source, I create two audio tracks (one mix-down to stereo and another AC3 passthru) - both of them are littered with audio pops throughout.

The Handbrake encoding log is FILLED with lines like this (see below) - in fact the video log is 514KB, 99.9% of which are due to endless audio sync problems. I'd say there's something wrong with the original source, except... the original source plays perfectly fine in both VLC and in WMP. The resulting file has audio pops no matter what player I use, so I think this is a Handbrake problem.

[11:12:07] sync: adding 75 ms of silence to audio 0x1 start 3062430, next 3055680
[11:12:07] sync: adding 75 ms of silence to audio 0x1 start 3062430, next 3055680
[11:12:07] sync: audio 0x1 time went backwards 54 ms, dropped 4 frames (start 3149730, next 3154590)
[11:12:07] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 3155130, next 3156510)
[11:12:07] sync: audio 0x1 time went backwards 54 ms, dropped 4 frames (start 3149730, next 3154590)
[11:12:07] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 3155130, next 3156510)
[11:12:10] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 3493980, next 3495390)
[11:12:10] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 3493980, next 3495390)
[11:12:17] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 4314780, next 4316190)
[11:12:17] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 4314780, next 4316190)
[11:12:17] sync: adding 74 ms of silence to audio 0x1 start 4339170, next 4332510
[11:12:17] sync: adding 74 ms of silence to audio 0x1 start 4339170, next 4332510
[11:12:18] sync: audio 0x1 time went backwards 42 ms, dropped 3 frames (start 4358430, next 4362210)
[11:12:18] sync: audio 0x1 time went backwards 42 ms, dropped 3 frames (start 4358430, next 4362210)
[11:12:18] sync: audio 0x1 time went backwards 20 ms, dropped 1 frames (start 4407390, next 4409250)
[11:12:18] sync: audio 0x1 time went backwards 20 ms, dropped 1 frames (start 4407390, next 4409250)
[11:12:19] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 4477950, next 4479330)
[11:12:19] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 4477950, next 4479330)
[11:12:19] sync: audio 0x1 time went backwards 21 ms, dropped 1 frames (start 4515840, next 4517730)
[11:12:19] sync: audio 0x1 time went backwards 21 ms, dropped 1 frames (start 4515840, next 4517730)
[11:12:41] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 7225470, next 7226850)
[11:12:41] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 7225470, next 7226850)
[11:12:42] sync: adding 74 ms of silence to audio 0x1 start 7351650, next 7344930
[11:12:42] sync: audio 0x1 time went backwards 63 ms, dropped 5 frames (start 7361280, next 7367010)
[11:12:42] sync: adding 74 ms of silence to audio 0x1 start 7351650, next 7344930
[11:12:42] sync: audio 0x1 time went backwards 63 ms, dropped 5 frames (start 7361280, next 7367010)
[11:12:42] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 7375230, next 7376610)
[11:12:42] sync: audio 0x1 time went backwards 15 ms, dropped 1 frames (start 7375230, next 7376610)
[11:12:43] sync: audio 0x1 time went backwards 15 ms, dropped 1 fra

[racer-x]

AC3 is not properly supported in an mp4 container, use aac for that. If you need to use ac3, then use mkv container.

[Fortissimo]

AC3 is not properly supported in an mp4 container, use aac for that. If you need to use ac3, then use mkv container.

Is this a problem "not properly supported" by the mp4/m4v file format in general, or a problem with Handbrake? I'm not trying to play the blame game, I just want to fully understand what the problem is.

If it's a problem with HandBrake, I don't suppose using m4v instead of mp4 would make any difference? I know m4v is the same thing as mp4 except more associated with Apple...

I prefer mp4 because some players do not support mkv. If it's a problem with HandBrake, does anyone know if this problem might be fixed soon?

[hello_hello]

The Handbrake encoding log is FILLED with lines like this (see below) - in fact the video log is 514KB, 99.9% of which are due to endless audio sync problems. I'd say there's something wrong with the original source, except... the original source plays perfectly fine in both VLC and in WMP. The resulting file has audio pops no matter what player I use, so I think this is a Handbrake problem.

Was the source file downloaded? If so was it definitely downloaded completely (100%)?

You might try opening the source file with MKVMergeGUI and saving it as a new MKV. If MKVMergeGUI offers any warnings in relation to timecodes or sync, there's probably a problem with the source file. If it doesn't complain, you could try re-encoding the new MKV anyway.

You could try extracting the DTS audio from the original MKV with MKVCleaver, then converting it to AAC or AC3 with something else. Once that's done you'll need to use MKVMergeGUI to add the DTS and/or the converted version to Handbrake's output and remove any audio Handbrake added to the output file, or if you need MP4 output, you should be able to do the same with MyMP4Box GUI. I don't work with MP4 much myself. MKVMergeGUI makes playing with MKVs so much easier.
Better than extracting the DTS with MKVCleaver might be to extract it with eac3to. MKVCleaver will just extract. Eac3to will try to fix any problems it finds and tell you about them in the log file. A GUI for eac3to. The links for an an updated version to work with the latest eac3to but I think it only comes in 64bit flavor. Either that or it doesn't play nice with XP. Or there's an updated version of the HD Streams Extractor under MeGUI's Tools menu if you happen to have MeGUI. (updated version)

[THRobinson]

I figured for my situation that it was specific files, probably an odd codec used or something. Played fine, converted poorly. I ended up using PopCorn MKV Converter, converting to AC35.1, then when using Vidcoder/Handbrake I just set the audio to pass through.

I know it isn't computer specific because I just built a new system less than 2 weeks ago, so, fresh new install of all software and drivers and all new hardware. Got a new copy of the file and had the same issue.

Rare, almost never an issue... 2 computers, 2 copies of the file... Must be something about how the original audio was encoded. But, the PopCorn method works.

[Fortissimo]

The source file is not incomplete. In fact, if a movie file ever is complete (i.e. it doesn't finish dumping to an ISO, or converting to an MKV or MP4), Windows Media Player won't even touch the file - it just hangs forever as it tries to figure out the incomplete file. But WMP plays this 10GB MKV source file just fine.

It seems to me that if Windows Media Player (which is inferior to VLC and other players out there) can handle the source audio with no problems from beginning to end of the movie, Handbrake ought to be able to as well.

Thanks for all the suggestions. Although they all seem like ways to put duct tape over a problem that is going to continue to occur in the future with different files (not just this one), it's still nice to have duct tape.

[THRobinson]

Well, for me it's happened maybe 5x out of about 150... so rather than spend time figuring it out, when it could be a source file issue which I have no way to correct anyways, I opted to duct-tape it and move on.

The files I had issues with, played fine in WMP and also XBMC/KODI which I use on my HTPC's.

[hogger129]

I get this effect if I convert with DVDFab. Using something like BDRB, it's not there. I see you are encoding from the DTS 5.1 track. Are you sure it's the DTS 5.1 track and not the DTS-HD Master Audio track?

[THRobinson]

I'm not sure who's being asked.

I use VidCoder, same as handbrake with a different GUI... Whatever audio track that's listed in the drop down is what I convert if it's DTS, if it's AC3/AAC I just passthrough. It's from MP4/MKV files, not direct from disc.

[Dougster]

I have had this issue with some discs in the past ('Gravity' was one of them).

Solution I came up with:

1. Don't downmix anything, if it's 5.1 keep it at 5.1 and let the media player handle it.

2. In Handbrake or Vidcoder attenuate the conversion by 1 dB (-1 in the settings) to avoid clipping.

Hope this helps.