# Audio-Video Sync Issues with Raw Data from Zoom SDK on Linux

**URL:** <https://devforum.zoom.us/t/audio-video-sync-issues-with-raw-data-from-zoom-sdk-on-linux/137408>\
**Category:** Meeting SDK\
**Tags:** recording\
**Created:** [September 16, 2025, 4:53pm UTC](https://devforum.zoom.us/t/audio-video-sync-issues-with-raw-data-from-zoom-sdk-on-linux/137408 "2025-09-16T16:53:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Venkat\_Koushik](https://avatars.discourse-cdn.com/v4/letter/v/c4cdca/32.png) [@Venkat\_Koushik](https://devforum.zoom.us/u/Venkat_Koushik)\
**Post date:** [September 16, 2025, 4:53pm UTC](https://devforum.zoom.us/t/audio-video-sync-issues-with-raw-data-from-zoom-sdk-on-linux/137408/1 "2025-09-16T16:53:18Z")

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**Description:**

We’re experiencing persistent audio-video synchronization issues when processing raw YUV video and PCM audio data from the Zoom Meeting SDK on Linux. Despite multiple approaches, we cannot achieve proper sync.

**Setup:**

- Linux Ubuntu 22.04, Zoom Meeting SDK
- Capturing raw YUV420 video via `onVideoRawDataReceived()`
- Capturing raw PCM audio via `onMixedAudioRawDataReceived()`
- Using FFmpeg for post-processing and composition

**Issues:**

1. **Variable video speed** : Video starts at ~1.5x speed, then settles to 1x
2. **Audio-video drift** : Constant lag between audio and video streams
3. **Timestamp inconsistencies** : Raw data timestamps appear unreliable

**Attempted Solutions:**

- FFmpeg `setpts` and `atempo` filters with various values
- GStreamer automatic synchronization with `videomixer`
- Multiple participant layouts (Stack Overflow style: 1 large + 3 small videos)
- Forced constant frame rates with `fps=30` filter
- Used Zoom SDK’s `GetTimeStamp()` method

**References:**

- Tried solutions from: [https://stackoverflow.com/questions/47959443/how-can-i-have-4-videos-as-1-using-gstreamer](https://stackoverflow.com/questions/47959443/how-can-i-have-4-videos-as-1-using-gstreamer)
- [Syncing Send Video and Send Audio in meeting SDK - #7 by amanda-recallai](https://devforum.zoom.us/t/syncing-send-video-and-send-audio-in-meeting-sdk/110080/7)

**Question:**  
What’s the recommended approach for maintaining proper audio-video sync when processing raw data from multiple participants? Are there specific timing considerations or SDK methods we should use for frame-accurate synchronization?

“We would also like to know how we can start recording automatically without the host’s help, whether the host is from our organization or a different one.”  
(Internal meeting or external meetings)

Any guidance would be greatly appreciated!

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**Author:** ![amanda-recallai](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/amanda-recallai/32/44747_2.png) [@amanda-recallai](https://devforum.zoom.us/u/amanda-recallai)\
**Post date:** [September 17, 2025, 10:04pm UTC](https://devforum.zoom.us/t/audio-video-sync-issues-with-raw-data-from-zoom-sdk-on-linux/137408/2 "2025-09-17T22:04:07Z")

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Hey @Venkat_Koushik, you could be seeing A/V drift and speed swings for several reasons:

- Early frames are using wall time or callback order instead of SDK timestamps
- Video pacing isn’t tied to a master clock, so the first seconds can run ~1.5× before settling
- PTS origin varies per stream, so audio and video start at different zeros and then drift

There are a few things you could try to sync A/V better though:

- Align all timings from SDK timestamps, not arrival time or system clock, using [`AudioRawData::GetTimeStamp`](https://marketplacefront.zoom.us/sdk/meeting/linux/class_audio_raw_data.html) and the [Linux raw data callbacks](https://developers.zoom.us/docs/meeting-sdk/linux/add-features/raw-data/)
- Buffer ~150–300 ms per stream as a jitter buffer, pick audio as master, normalize each track to t=0, and pace the video by drop/dup to your target FPS
- If capture rate drifts, resample audio to the master clock and keep video aligned; Zoom’s guidance is to [timestamp each audio and video frame](https://devforum.zoom.us/t/syncing-send-video-and-send-audio-in-meeting-sdk/110080/8) and ensure they are played back in sync

On how to auto-start recording for internal or external meetings, you can [get a meeting’s join token for local recording](https://developers.zoom.us/docs/api/rest/reference/zoom-api/methods/#operation/meetingLocalRecordingJoinToken) to have your bot automatically start recording after it enters the call; this generally works for meetings owned by the authenticated user/app.

If you’d rather not build and maintain the buffering and sync layer, teams often use [Recall.ai’s meeting bot API](https://www.recall.ai/product/meeting-bot-api) to pull real-time Zoom audio, video, and transcripts and offload multi-participant timing and layout orchestration