On Thu, 9 Feb 2023 11:04:31 -0800 Steven Kan <[email protected]> wrote: > > On Feb 9, 2023, at 8:09 AM, Anatoly <[email protected]> > > wrote: > > > > Hello, > > On Wed, 8 Feb 2023 16:11:39 -0800 > > Steven Kan <[email protected]> wrote: > > > >>> On Feb 7, 2023, at 10:56 PM, Ferdi Scholten <[email protected]> > >>> wrote: > >>> > >>> I have a Windows PC running Blue Iris security camera software, > >>> and it has a "Direct-to-disc" option whereby it records video > >>> straight from each camera's h.264 RTSP stream without > >>> transcoding, to reduce CPU and HDD utilization. There is some > >>> re-packaging involved, and I think that's where the problem may > >>> lie. > > But are you sure that there is re-packaging? > > What if capture camera stream with ffmpeg itself? > > ...snip... > > Good question. "Repackaging" may be the wrong word, but BI must do > something to take an RTSP stream and turn it into a file on a disk. > There is no transcoding occurring with BI's "direct-to-disc" feature, > because the reason for that feature is to reduce CPU utilization, and > Task Manager on the BI computer shows that it's very, very low. But > BI must at last write some sort of file name, file header, EOF > marker, etc., right? Right. File called 'container'. There are many container formats like: mp4, avi, mkv... For each container format there is standard that describes what exactly should be file header, delimeters between audio/video chunks, EOF and more. Almost every format has something like complex 'delimeters' between chunks of audio/video data or even more complex 'sub-containers'. So almost never you can just cut off start and end of the file, and get 'raw stream' and play it. Here is internals of mp4 format for example: https://dev.to/alfg/a-quick-dive-into-mp4-57fo If some software can't play some file, there are two possibilities: -software doesn't know how to decompress video data -software doesn't know how to extract video data from your container. So I think that would be nice to perform full test for sure: Record RTSP stream to mp4 file (w/o recompress, of course, -c copy) with ffmpeg, then bring file to your AS MAC and test. Another question is how did you got that >> Bad (original) file: >> https://www.kan.org/download/BlueIris/TrailDown.20230203_042912-042924.495.mp4 Are 'BI' creates such a files automatically every N munutes and you just copied one from that windows PC disk with 'windows explorer'? Or there is some 'export' procedure need to be executed within 'BI' interface? If so, is 'mp4' container format only option? Or there are others, like, say 'avi'? This file looks like mp4 container by header, but if we assume that h264 data inside it valid, then container itself is not standard mp4 (like some extra non-standard 'delimeters' that pulled along vith h264 data as garbage). By the way, list of container formats that ffmpeg can handle: ffmpeg -formats ffmpeg tries to guess container format automatically, but can be told to threat input as specific format by -f <format>
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