Recover H264 encoded ts segments that dont have PPS/SPS

[vinod kesti]

Hi Guru.
The data used may not be in NAL format. Simply appending SPS and PPS may not helpOnce you pack SPS and PPS as NAL then pass that buffer to the mpegts muxer. or h264parse can do it for you if you set sprop parameter in the rtph264parse.


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    On Wednesday, 3 May, 2023 at 08:43:09 pm GMT-5, Nicolas Dufresne via gstreamer-devel <gstreamer-devel at lists.freedesktop.org> wrote:  
 
 

Le mer. 3 mai 2023, 21 h 15, Guru Govindan <gurunathan.govindan at gmail.com> a écrit :

Hi Nicolas,Thanks for your response, I figured out a way to extract the h264 header by making another connection to the camera and extracting data from the first stream. I used help from here https://stackoverflow.com/questions/24884827/possible-locations-for-sequence-picture-parameter-sets-for-h-264-stream/24890903#24890903
I also verified that the extracted header is valid by running `ffmpeg -i header1.h264 -an -c:v copy -bsf:v trace_headers -f null` and verified that it is a valid h264 file and contains SPS and PPS values.
However when I cat the recovered header and copy the truncated file, it says it is not a valid file.
Any ideas? Should it be inserted before every keyframe and not just in front of the file?


You only need it once, unless you had dynamic resolution change (which never happen with security cam). My guess would be the stream format (avec vs byte-stream), you want byte stream for mpeg ts.



On Wed, May 3, 2023 at 12:47 PM Nicolas Dufresne <nicolas at ndufresne.ca> wrote:

Le mercredi 03 mai 2023 à 10:22 -0700, Guru Govindan via gstreamer-devel a écrit :
Hi There,
I am having an issue where a lot of video footage from a security camera was recorded without the sprop-parameters-set (SPS/PPS).
I am unable to play or transcode these ts files as it does not have SPS/PPS values. 
I tried the following by sending the h264parse the stream format but that failed

The only way to recover is to find the origin SPS/PPS, note, this is static on most cameras. The sprop-parameters contains it, just it may need to be transformed. Then something like this may work, but never tried`

gst-launch-1.0 \
  filesrc location=truncated.ts ! tsdemux ! filesink location=truncated.h264
cat recovered-header.h264 > fixed.h264
cat truncated.h264 >> fixed.h264gst-launch-1.0 \  filesrc location=fixed.h264 ! h264parse ! mpegtsmux ! filesink location=fixed.ts
This is video only though, totally untested.

Nicolas


```gst-launch-1.0 -v filesrc location=2.ts ! tsparse ! tsdemux name=demux demux. ! queue ! h264parse ! video/x-h264,stream-format=avc,alignment=au ! decodebin ! videoconvert ! vaapih264enc ! h264parse ! mpegtsmux alignment=-1 ! filesink location=output.ts
```failed with /GstPipeline:pipeline0/GstH264Parse:h264parse0.GstPad:sink: caps = video/x-h264, stream-format=(string)byte-streamERROR: from element /GstPipeline:pipeline0/GstH264Parse:h264parse0: No valid frames found before end of stream
I then tried to split it as per keyframes and then mux it.. like below but that failed as well
```gst-launch-1.0 -v filesrc location=2.ts ! tsdemux name=demux ! h264parse ! splitmuxsink max-size-time=1000000000 location=segment%02d.ts mpegtsmux name=mux ! filesink location=output.ts demux.video_0 ! queue ! mux.
```failed with h264parse0: No valid frames found before end of stream
Since it could not find EOS.. I thoiught of sending the entire manifest.. but that didnt work as well
```gst-launch-1.0 -v filesrc location="<manifest uri>" ! hlsdemux ! h264parse ! video/x-h264,stream-format='(string)avc,alignment=(string)au' ! mpegtsmux ! h264parse config-interval=-1 ! mpegtsmux ! filesink location=output.ts
```
Just like how we can add config-interval to a rtp stream, is there a way to add it to a ts segment?
Best Regards,Guru




  
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