chapter marks always shifted backwards by few seconds up to minutes

[KonScience]

Hello!

We have a problem with shifted audio-playback in the web-player. Chapter marks imported from Audacity to Auphonic are displayed correctly, but clicking on them starts playback earlier (few seconds to minutes). At first we thought that was a result of us not using a "00:00:00 Intro"-mark like many other podcasts do and as shown in Auphonic's tutorial, but the problem also occurs when we do use this additional mark.

Strangely, the shift is:

• not exactly the difference between 00:00:00 and the 1st regular mark
• different from episode to episode
• and different between the chapters of the same episode

The episode asset we use is MP4 chapters.txt. Switching to "manual entry" doesn't help & PSC causes the entire chapter list to vanish from the web-player.

Any hint would be helpful. Maybe it's an Auphonic problem, although reproducing a show with the 00:00:00-mark didn't help. Or maybe it's already an Audacity problem, but the label times in the file it exports are exactly as they were set and as they are displayed by the Podlove Web Player. It seems to be a problem with playing the MP3 (tested in Firefox) at the correct time point. Thanks for any help and many greetings!

Here's Podlove's support info:

Website             http://www.konscience.de
PHP Version         5.4.4-14+deb7u7
WordPress Version   3.8.1
Publisher Version   1.9.10-alpha
Web Player Version  2.0.17
curl Version        7.26.0
iconv               available
allow_url_fopen     1
simplexml           ok
max_execution_time  60
upload_max_filesize 50M
memory_limit        256M
disable_classes     
disable_functions   
permalinks          ok
podcast_settings    
web_player          ok

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Nice, Everything looks fine!

[gholzmann]

It would be great to find out where the problems lies. Can you check manually, if your chapter times (as shown in the webplayer) are correct? Are chapters in podcast players (e.g. instacast, antennapod, ...) also wrong? Or only in the web player?

[KonScience]

Hi Georg, thanks for these hints!

[...] Can you check manually, if your chapter times (as shown in the webplayer) are correct?

They are displayed correctly, but the actual audio comes later. I test-listened to about 3 chapter marks each in 3 episodes & found the delay to be anywhere between 10 & 70 sec. Calculated by subtracting the displayed time-stamp at the chapter start from the actual time the correct audio section starts.

Are chapters in podcast players (e.g. instacast, antennapod, ...) also wrong?

In AntennapPod on Android 4.2, 4.3 & 4.4 the delay is noticeable, but much smaller. Maybe just an artifact of rounding the milliseconds up or down, that Auphonic writes into the chapter marks.

Or only in the web player?

Yep, only there. However, after testing other browsers & audio asset formats available to the Web Player, I'm now sure it's only MP3s in Firefox. M4A, Opus & Ogg do not have this delay, and neither do Safari & Chrome in any format. So, it can either still be the Web Player, or Firefox itself. As a work-around for our podcast, we'll use start using .ogg files.

A side question just out of curiosity: are there fallbacks to preferred formats per browser? They all played episodes just fine, even if all audio assets were set to "unused" in Podlove's Web Player settings.

[timpritlove]

Podlove Publisher 1.9.12 preserves chapters when switching to "manual entry" so this should work now.

[KonScience]

Unfortunately not, but by now I'm sure it's a problem in Firefox' MP3 loading. Letting the Web Player use OGG solves the problem.

[timpritlove]

Not sure this is really an issue with Podlove Publisher

[pommes]

I have the same issue at http://zahlensender.net with Firefox 29 and 30 (OSX). Chrome 35 and Instacast 4.6 both start playing at the right position when clicking the chapter mark. Maybe it's a Firefox only issue?

[KonScience]

Yes, it must be. They track the issue here.