Video playback issues: no audio on Mac?

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Video playback issues: no audio on Mac?

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AKrishna	AKrishna posted 4 Months Ago Topic Details Share Topic
Group: Forum Members Posts: 93, Visits: 281	In my current running study (https://mili2nd.eu/bwec), participants watch several (German) videos showing debates on various topics. During data collection, three (of around 80) participants contacted me and mentioned that they were able to hear my technical check video's audio fine, but couldn't hear any audio during the main part of the experiment. Two kindly mentioned that they were using Macs and running Chrome. I checked some of the previous forum topics on encoding videos before starting the experiment and settled on H264 - MPEG-4 AVC video and MPEG Audio layer 1/2 (mpga) audio codecs (as listed by VLC). Is this a known issue for that kind of file? For reference, the test video showed as H264 - MPEG-4 AVC (part10) (avc1) / MPEG AAC Audio (mp4a). I realize I probably should have made sure my test video was encoded identically to the main videos - this is probably a codec issue. I just thought I'd mention it in case anyone else runs into the same issue. I imagine bundling codecs with Inquisit in the same way as VLC does is in the realm of fantasy, right? A man can dream... ;)
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Dave	Dave posted 4 Months Ago ANSWER Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	+x AKrishna - 1/5/2024 In my current running study (https://mili2nd.eu/bwec), participants watch several (German) videos showing debates on various topics. During data collection, three (of around 80) participants contacted me and mentioned that they were able to hear my technical check video's audio fine, but couldn't hear any audio during the main part of the experiment. Two kindly mentioned that they were using Macs and running Chrome. I checked some of the previous forum topics on encoding videos before starting the experiment and settled on H264 - MPEG-4 AVC video and MPEG Audio layer 1/2 (mpga) audio codecs (as listed by VLC). Is this a known issue for that kind of file? For reference, the test video showed as H264 - MPEG-4 AVC (part10) (avc1) / MPEG AAC Audio (mp4a). I realize I probably should have made sure my test video was encoded identically to the main videos - this is probably a codec issue. I just thought I'd mention it in case anyone else runs into the same issue. I imagine bundling codecs with Inquisit in the same way as VLC does is in the realm of fantasy, right? A man can dream... ;) Yes, probably an encoding issue (https://discussions.apple.com/thread/8117403; https://discussions.apple.com/thread/2541659; you can find many more); not an Inquisit issue per se. Every system is different, and operating systems -- including macOS -- do have bugs related to video / audio playback. The browser used doesn't factor into this, Inquisit Web experiments are not executed in the browser. Building codecs into the Inquisit Web app is problematic, as it would immensely increase the download size of the player app -- take a look at the size a VLC installation occupies on your disk to get a sense of the scale. And then there are potential licensing issues (the codec intellectual property space is a mess).
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