Audio falls out of sync

[Chris Husband]

Hi. I recently purchased the license for your Download App. It works but every video I have download from one site suffers from the audio falling badly out of sync by the end of the video. I bought the App soley to get the video's posted by one user on Youtube. I'm not happy with the results. I've downloaded 20+ and they are all out of sync.

Also, I didn't get an email acknowledging my payment so I've been ripping my hair out trying to contact you as there is little or no contact information with the App. Not happy. I'd like a full refund. 

I can send you links for the Video's in question and you can try for yourself. I think it is because the audio streams of the videos in question were encoded at a variable bitrate not constant. The app re-encodes and is unable toreplicate the variable bitstream rate at the crucical points. Most of the performance are an hour + so the audio drifts out of sync by 7-8 frames by the end of the video. So the app is of NO USE to me. My other option is to contact Visa and log a complaint. 

I look forward to your response. Chris.

[mig]

No one else has reported the problem. Could you share one video page URL and let us know which variant you pick exactly ? Are you using conversion or just aggregation ? If you use conversion and setup your own conversion configuration, it's indeed easy to get that kind of issue.

[Chris Husband]

Hi. Thanks for the reply. First of all no license purchase notifiaction email recieved post purchase. That includes by my Junkmail folder.

 Not happy about that for starters as contact is anything but easy without it. Feeling like I've been ditched after paying my 30 bucks. Regardless, Here's al ink.

https://www.youtube.com/watch?v=23PI5hcBzYI

One of 20 or so I downloaded by the same Poster (MV). each and every one of them falls out of sync. The offset gets worse the deeper into the footage you go. I do straight downloads (no re-encoding) and select the DL version with the biggest file size (best quality). I've used FFMpeg to unpack the MP4 downloads to Uncompressed AVI and PCM audio so I can then load the audio into Wavelab and time stretch it (reduce length) to get it close to being in sync. 

WAY TOO MUCH WORK for files that are marginal to begin with. Not happy with the return on my investment. I'm no amatuer. I've archived thousands of hours of unreleased audio and video footage for some of the biggest rock bands of the last 30 years. I await your input. Thanks. Chris.

[mig]

Our system automatically sends an email on license purchase. Maybe we have a bug that causes your address to behave otherwise, must most likely there is one of the mail servers between you and us deleted our email. I can send you privately the license key and link to the invoice if you want.

I just downloaded the 1:40:48 concert video from your link, in an ADP variant, corresponding to:

audio:   Duration: 01:40:47.87, start: 0.000000, bitrate: 128 kb/s
    Stream #0.0(und): Audio: aac, 44100 Hz, stereo, fltp, 125 kb/s

video:   Duration: 01:40:48.17, start: 0.000000, bitrate: 496 kb/s
    Stream #0.0(und): Video: h264 (Main), yuv420p, 640x480 [PAR 1:1 DAR 4:3], 493 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc

The automatic audio and video aggregation produced a perfectly synchronized media.

Could you just try to download a non-ADP variant of this video just to validate your player ?

[Chris Husband]

Hi. Just downloaded another non ADT version. MAYBE slightly better but still at least 3-4 frames out of sync by the end. Try going to the one you download and view the last 2-3 minutes and see if it's in sync. As mentioned the deeper you go the worse it gets. I'm using Media Player Classic to view on laptop. They are out of sync when loaded into Adobe Premiere or After Effects as well. I'll download a file from a different uploader and see what happens. I think it's because the audio is encoded with a Variable Bitrate...not Fixed.

[mig]

If a non-ADT (meaning a single monolithic server-built file) video plays out of sync, then your player is at fault.

There are a couple of things you should try:

- play the video using VLC (from http://videolan.org/). This is a much better and compatible player than Windows Media Player.

- when you download the video (or after you did so), convert to an AVI file. AVI uses a different internal indexing mechanism than MP4. Maybe it will work better with WMP.

[Chris Husband]

Why then does this one downloaded with the same app play back perfectly in sync with the same player in sync. It's also posted on YT but by a different user. No issues.

https://www.youtube.com/watch?v=WGI99kQ13hA

Not buying the last reply because when I decode the MP4 to dedicated uncompressed AVI audio and video streams and then drag both streams into Premiere the audio timeline is ALWAYS at least 7-8 frames longer than the video file in length. Without exception. The offset is dependent on the length of the footage. The longer the footage running time the more the audio file exceeds the video file in length. It's offset end of story lol.

[Chris Husband]

I just downloaded VLC. I don't know what you are watching....but it's no different. The sync isn't even close by the end of the videos lol. It only seems to be an issue on the videos posted by MV on YouTube. As mentioned the other link I sent is money....no problem.

Now, I'm even less happy. An app that's not delivering for my dollar and I'm loading my laptop up with players that I don't need because the issue still exists when viewed with them. Let me know how we are going to proceed. I'm not satisfied. Two options at this point. Refund or I lodge a grievance with Visa. As mentioned I unpacked the MP4's with the sync issue with FFMpeg as dedicated audio and video streams. Uncompressed AVI and PCM audio. When I drag both files into Premiere and drop them on the same timeline to edit the audio file is  about .5% longer than the video file. I can see this visually so I won't be convinced latency isn't being introduced into the audio stream at some point before my point in the food chain.

[Chris Husband]

Hello? How do I go about securing a refund?

[mig]

Please send me in private the email you used to purchase the license as it is not the one you use in this forum.

[Chris Husband]

Hi. It's chris_...@hotmail.com

I've downloaded about 30 of those MV (Master Vault) posted concerts on YouTube. I'd say maybe 4 are in sync by the end of the video. The latency appears to be worse on some than others. I've gone back and watched the posted footage of the ones with sync issues and the issue isn't present on the originals.. Something in the food chain. If you want links to the ones that are free of the issue I can provide. 

Looking at their encode properties vs ones that are out of sync may provide the answer. I'm too frustrated to bother at this point.

[Patrick Tollgren lazarov]

I had the same problem especially from http://urplay.se
The sound was out of sync in lowres or the video was shuttering and broken I highres.
The playback in Firefox on urplay.se is also a bit laggy so its not only in the downloaded mp4.

The solution for me was sadly to switch to Chrome and fvddownloader. The playback in Chrome worked smoothly but Downloadhelper couldn't find any videostreams on urplay.se
The conclusion is that the problem with audiosync is in Firefox and not in DownloadHelper. Downloadhelper in Firefox is still my preferred choice on sites there it works ;)

[mig]

I must say i was surprised fvddownloader could capture HLS streams so i gave it a try on Chrome. The only thing fvddownloader could get is the swf file (basically the flash program that acts as a player). Are you running this swf with a local Flash player ? Note that you can enable swf capture on VDH: open settings > Behaviour, check Advanced, add "swf" to the list parameter "Detect extensions".