Hikvision MP4 won't play or has no sound
Many Hikvision and HiLook recorders export clips as MPEG program streams with a 40-byte Hikvision header (it starts with IMKH) and only name them .mp4, so players refuse them or play them with the wrong length. Their sound is usually G.711, a telephone codec MP4 players don't support. Rewrapping the video as a real MP4 and converting the sound to AAC fixes both, and the picture isn't re-encoded.
Which problem do you have?
| What you see | Why | What fixes it |
|---|---|---|
| The file won’t open, or VLC shows the wrong length | It’s an MPEG program stream with a Hikvision header, named .mp4 | Rewrap it as a real MP4 |
| It plays, but there’s no sound | The sound is G.711, which MP4 players don’t play | Convert the sound to AAC |
| VLC shows one still frame and stops | A real MP4 with G.711 µ-law sound, a known FFmpeg and VLC problem | Convert the sound to AAC |
| Sound, but no picture | The video is H.265 (HEVC), which some players and browsers can’t show | Install HEVC support, use VLC, or export H.264 |
| Nothing plays at all, even in VSPlayer | Video encryption is on in the EZVIZ or Hik-Connect app | Turn encryption off and export again |
Fix it in your browser
- Open Hikvision to MP4 and add the exported files. Several at once is fine.
- Each file is rewrapped into a real MP4 on your device in a few seconds. The video is copied, not re-encoded, so the picture stays exactly the same; only G.711 sound is converted to AAC.
- Download the MP4s, or all of them as one ZIP.
The files are never uploaded: the converter downloads once to your browser and runs there. With renaming on, 192.168.1.64_01_20231105142233123.mp4 becomes 192.168.1.64_2023-11-05_14-22-33_CH01.mp4, so exports from two recorders don’t collide, and the time from the name is saved as the MP4’s creation date.
To keep only the part you need, press Trim this clip on the file’s row. The video trimmer opens with that MP4 and names the clip by the recorder’s clock.
Play it on Windows without converting
Hikvision’s VSPlayer and iVMS-4200 play these exports on Windows. That’s fine for watching, but the file still won’t play for the people you send it to, and neither app turns it into a normal MP4 reliably. For sharing, convert it.
EZVIZ and Hik-Connect: encrypted clips
With video encryption on, the camera scrambles the footage with its verification code, and only the EZVIZ or Hik-Connect app can play it. No converter can read it. Turn encryption off in the app, then record or export the clip again.
Sound but no picture: H.265
Newer Hikvision cameras record H.265 (HEVC, sometimes called H.265+). The MP4 keeps that video. It plays on iPhone, Mac and Android, and in Chrome and Edge on most recent computers. On Windows, install Microsoft’s HEVC Video Extensions; VLC plays it everywhere. To avoid it, set the camera’s main stream to H.264 in the recorder’s video settings.
Sources
- FFmpeg ticket #9306: a real Hikvision MP4 with G.711 µ-law sound plays as a still frame; copying the video without the sound works.
- VLC issue #25864: the same files in VLC, fixed by converting the sound to AAC.
- FFmpeg-user mailing list, December 2017: an NVR export with the IMKH header plays without sound and with wrong timing.
- Microsoft Store: HEVC Video Extensions: H.265 support for Windows.
Questions
Why does my Hikvision video have no sound?
Hikvision cameras usually record sound as G.711 (A-law or µ-law), a telephone codec that MP4 players such as Windows Media Player, QuickTime and phones don't play. Converting the sound to AAC, which every player handles, brings it back. The picture is copied as it is.
Why won't my Hikvision .mp4 open in Windows Media Player or QuickTime?
Because it usually isn't an MP4 inside. Hikvision exports are often MPEG program streams with a Hikvision header, saved with the .mp4 extension. Players that expect a real MP4 refuse them. Rewrapping the same video into a real MP4 makes it open everywhere.
What is an IMKH file?
IMKH are the first four letters of the 40-byte header Hikvision writes in front of its MPEG program streams. The header describes the camera's video and audio; the video behind it is ordinary H.264 or H.265. FFmpeg and VLC read it, most other players don't.
Can I play Hikvision files on a Mac?
Hikvision's VSPlayer has a Mac version that plays them, but it can't convert them, so the file still won't play for anyone you send it to. Converting to MP4 in the browser works on a Mac too and gives you a file that plays everywhere.