Webcams

[Khabarakh]

Specs:

Logitech HD Webcam C270

Windows XP x64

Logitech Webcam Software 2.10

Task: record 720p video@30fps

First i tried using LWS, of course just getting 15fps video.

Next i tried various 3rd-Party-Tools, always just getting 15fps.

Disabling RightLight resulted in 30fps when using 3rd-party-tools (Virtualdub, Debut, MyCam, webcamxp 5).

BUT

When i record with 3rd-party-tools, audio is always out of sync, lagging behind beween 400 and 1200ms!

CPU-load is minimal, as is HDD-usage. USB2.0 direct port is being used and switching between uncompressed video and on-the-fly encoding does not change anything.

So how do i get synchronous audio/video@30fps when recording with anything other than LWS?

[KachiWachi Distinguished Logi Legend]

Welcome to the Logitech Community Webcam Forum Khabarakh!


Please provide a sample video that illustrates this condition for evaluation.



Thanks.

[Khabarakh]

Video available here: URL removed to keep my bandwidth-usage low

640x480, 30fps, 30s, Filesize 12.7MB

low resolution and xvid-compression (applied after capture) to keep the filesize down.

Audio-lag is about 1000ms

[KachiWachi Distinguished Logi Legend]

Does this issue occur when the camera is installed in UVC Mode?



Thanks.

[Khabarakh]

Uninstalled the Logitech-driver, recorded in UVD-Mode. Same as before.

Additionally, UVD-mode seems limited to 10fps@720p. 30fps@640x480 is possible, no change with the sync-problem.

[Khabarakh]

As there seems to be no easy solution to my problem, i'd like to ask the other forum members if they have experienced similar, especially with the C-series Webcams and the C270 in particular.

For a temporary solution I now capture uncompressed, then resync the audio and then encode the video, but as this generates huge files (about 1GB/min ) it is not practical for longer videos.

Somehow LWS manages to record and on-the-fly encode video with audio in sync. If not for the 15fps-limit, the software would be perfect. Allowing the software to capture in 30fps would be great, adding an expert mode (ability to select resolution, framerate, bitrate, maybe even codec) would make my day.

[KachiWachi Distinguished Logi Legend]

---

Khabarakh sez -

For a temporary solution I now capture uncompressed, then resync the audio and then encode the video, but as this generates huge files (about 1GB/min ) it is not practical for longer videos.

---

OK.



Thank you for reporting back in with your progress and updated status.

[Khabarakh]

No progress on the initial problem yet, but additional info and more elaborate temporary solution:

as with the logitech software, videochat via skype is without delay.

Filesize when recording with virtualdub can be greatly reduced by directly encoding to divx. resyncing the audio later is still required, but video file sizes are now manageable.

The audio delay turns out to be consistently 1000ms (=1s). Maybe a buffer somewhere in the signal path? It's not in Virtualdub as it is in every 3rd-party-software i tried, which leaves the webcam-hardware and the webcam-driver. Anyway, it's just a speculation atm.

[KachiWachi Distinguished Logi Legend]

What is the make/model of your PC?



Thanks.

[Khabarakh]

PC is self-built. System overview is available here: http://www.sysprofile.de/id93198