Sound ok but video is black on Zmninja IOS

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fennec
Posts: 59
Joined: Thu Mar 20, 2014 1:17 am

Sound ok but video is black on Zmninja IOS

Post by fennec »

Hi

I try to record with audio on Escam 360 eye

I select H264 passthrough and audio stream

rtsp://admin:admin@10.0.0.208:554/onvif1
UDP

All is ok live view and record on Chrome without sound but i think is AAC codec

But on Zmninja sound is ok but no Video, it's black

If i download video from zmninja and i read on pc with VLC i have video but no sound

Output #0, mp4, to 'essai.mp4':
Metadata:
title : H.264 Video, RtspServer_0.0.0.2
encoder : Lavf58.45.100
Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuvj420p(pc), 896x896, q=-1--1, 5 fps, 10240 tbn, 5 tbc
Metadata:
encoder : Lavc58.91.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 8000 Hz, mono, fltp, 48 kb/s
Metadata:
encoder : Lavc58.91.100 aac


DO you know why
thanks
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iconnor
Posts: 2900
Joined: Fri Oct 29, 2010 1:43 am
Location: Toronto
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Re: Sound ok but video is black on Zmninja IOS

Post by iconnor »

Sounds like the timestamps are out of sync.

Almost every problem I've had with getting video storage to work has been about the timestamps. Sounds like I need to get access to this cam and figure out what magical thing it is doing.

So to explain:
We record from camera and there are two streams, 1 for video 1 for audio and each packet has a timestamp. Let's say they start from 0 (they don't always). At some point we want to start recording, so first I seek back in our buffer and find a keyframe (video has to start with a keyframe). It will have a timestamp of 123456789. (timestamps aren't always seconds. Each stream will likely have it's own timestamp units. Video is often second/90000 audio is often 8000Hz). So I take that first keyframe and it's timestamp, save the timestamp, alter it to 0 and then use the saved timestamp to calculate the timestamp of all the other packets I write to the mp4. But we have to convert units, Deal with negatives, out of order packets, buffering delays, etc. It's a nightmare.
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