Buggy Audio Delay for v. 0.7.1.4450

[meRobs]

I have Windows XP2 and when converting VOBs (currently a PAL) to AVI for use in Adobe Premiere CS3, I use:
AVI container with
DV Video at max bitrate via FFmpeg encoder
IMA ADPCM audio at max (1024) and 44.1 kHz via FFmpeg encoder.
The only problem is that the audio is always seems to be delayed by 6 frames (240 ms).
The slightly slower App, Kate's Toolkit, overcomes the problem with 6 extra video frames at the start (uses the Panasonic DV Codec I had on PC).

So, I tried the Audio Delay on the Time tab.
Unfortunately, any value inserted here is not transferred to Settings > Overall > Audio Options > Delay of audio track 1, which by default is 0 ms.
Hence, on entering -240 ms on the Time tab, the value is overwritten by the default, as set under Settings, as soon as processing begins.
I can overcome the problem by entering a value under Settings, etc, which is kept and the delay works.
To always have to get into Settings to change the delay is a pest and, presumably, not intended by the designer of this great App.

Please arrange for changes made on the user tabs to appear under settings -- other changes do appear, such as a change in encoder,etc.

By the way, my main use is to convert VOBs and FLVs into a form suitable for Premiere, with the highest quality.
So far, MediaCoder does a better job than Super 2009 and Kate's Toolkit, apart from this one slip!
Thanks.

[meRobs]

Another apparent inconsistency (BUG?)!

Under Settings > Audio Filters > Delay, Enable = False if not set
and the next 6 lines give the previously used delay (for 6 CHs) and the 'false' is tramslated to
Settings > Overall > Audio Options > as a Delay for Track 1 = 0, etc.

However, when saving settings as a Preset, the command "Enable = false" is not copied in.
Hence, it is not possible to have a Preset that includes a particular delay to overwrite current settings that have no delay.
Alternatively, to have a Preset that overwrites and kills a finite delay!

[meRobs]

On further investigation I find that the video delay in a VOB is not a constant, as mentioned earlier, but varies.

Indeed, the value of Video delay is displayed for any VOB in the application MediaInfo (under Audio).
If the audio is delayed by an amount equal to the existing video delay, the output is accurately in sync (in my case, in an AVI)!

So, every VOB to be converted in MediaCoder needs an Audio Delay set equal to the video delay given in MediaInfo.
However, I can find no way of setting such a Delay except under Settings > Overview > Audio Output > Delay of track 1, etc.

The Delay settable on the Time tag does not work! It is overwritten by the zero set under Settings (above).

Also, the Delay on the Sound Tab does nothing!

Why are there 2 tabs for setting a Delay?

[nosignal]

I've been having audio sync issues too, but in a different situation, so my help is more general.

Note that there can be lag introduced at two points: the decoder OR the encoder.

Converting videos from stills cameras to MP4 (aac audio) I found different codecs lagged by different amounts, but only 1 codec had no lag- FAAC. Its quality is not as great, but with a higher bitrate it is ok (and really, the audio bitrate is negligible anyway).

So maybe try isolating the problem to decoder or encoder. One thought would be to test the decoder, transcode to something known to work well (maybe even uncompressed) - if it still lags its the decoder. You can choose different decoders and monitor the change. Good luck.


But I second your concerns - loosing sync is a huge pain, especially when the interface does not work as expected.

[nosignal]

I tried some audio delays (MP4, H264, FAAC AAC, using only first 10 seconds):

Under the Sound tab:
- Delay of 1000 works.
- In my opinion it should say "Delay (ms)", but anyway, it works.
- However, -1000 does not work. This is indeed a bug, and if your audio is lagging, it is what you need!

Under the Time tab:
- Delay of -1000 does nothing. After rendering, it is reset to 0?!
- Delay of 1000 does nothing. After rendering, it is reset to 0?!

So definitely confirmed there are a number of bugs here. And these bugs are critical since audio is often out of sync and needs to be re-synced manually.

[meRobs]

Thanks for the confirmation!

Unfortunately, most VOB files that I have examined with the App MediaInfo have negative Video Delays!
Hence, a negative Audio delay of the same size is required.

Your results also confirm why the 'Delay' value set on either the Sound tab or the Time tab do not work (negative values).
Also, as stated above, the default zero value in Settings overwrites the value on the Time tab as soon as processing begins.

This is also why I requested on another post that MediaCoder diplays the value of Video Delay indicated by MediaInfo in the Propertites panel!
Let's hope Stanley has the time to read this Post and has the time to implement the changes (bug fix & add the Delay value)!

It would be even better if MediaCoder could remember different values of Delay for all files so that batch converting can happen!!
Fingers crossed!