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• avcodec/codec, allcodecs : Constify the AVCodec API

  25 février 2021, par Andreas Rheinhardt

  avcodec/codec, allcodecs : Constify the AVCodec API
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] doc/APIchanges
  • [DH] doc/examples/demuxing_decoding.c
  • [DH] doc/examples/muxing.c
  • [DH] doc/examples/transcode_aac.c
  • [DH] doc/examples/transcoding.c
  • [DH] doc/examples/vaapi_encode.c
  • [DH] doc/examples/vaapi_transcode.c
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/codec.h
  • [DH] libavdevice/dshow.c
  • [DH] tests/api/api-band-test.c
  • [DH] tests/api/api-flac-test.c
  • [DH] tests/api/api-h264-test.c
  • [DH] tests/api/api-seek-test.c
  • [DH] tools/target_dec_fuzzer.c

• Trying to emulate a hardware camera with a stream from a raspberry pi/picam ?

  19 avril 2021, par John Doe

  I have a raspberry pi and pi cam v2 connected to wifi. I am trying to stream the camera feed to a laptop over wifi, then make that stream appear as if it were a hardware camera on the laptop. I want to do this in order to get it into some other software that requires a hardware camera (can't rewrite this software, just have to work around it).

  


  I am running ubuntu 18.04 on the laptop. From my research, this should be very possible using some combination of ffmpeg and vfl2loopback. I started out by installing this library to stream the camera to a webserver : https://github.com/silvanmelchior/RPi_Cam_Web_Interface This works, and I am able to access the camera stream in my browser at http://10.0.0.47/http I set it up with no username/password for simplicity. I believe the camera port is 80 based on nmap output.

  


  I am now trying to redirect the stream on my ubuntu laptop. Based on my research and experimentation, this command is the closest I've come :

  


  ffmpeg -re -i http://10.0.0.47/html -map 0:v -f v4l2 /dev/video0

  


  (or also the same with port 80 instead of /html, not sure if this matters) :
ffmpeg -re -i http://10.0.0.47:80 -map 0:v -f v4l2 dev/video0

  


  This seems to work at first, but then produces the following error :

  


  http://10.0.0.47:80 : Invalid data found when processing input

  


  From googling, this may be due to the wrong kind of stream coming out of the rpi_cam_web interface, but I am not sure if this is true and if so how to fix it. I also investigated the html code of the page that accesses the webserver, and I can see that it is sending a series of jpgs, that change constantly with timestamps in the file name. So maybe this the issue, but again, unsure.

  


  Any ideas ? Help would be much appreciated.

  


  Edit : I tried another method, which seems to get a little further on, but am still running into issues :

  


  (on the pi) : raspivid -o - -t 0 -n -w 320 -h 240 -fps 30| cvlc -vvv stream :///dev/stdin —sout '#rtpsdp=rtsp ://:8000/' :demux=h264

  


  —>this starts a stream that I am able to succesfully view in VLC media player

  


  (then on the host system) : gst-launch-1.0 -v rtspsrc location=rtsp ://10.0.0.47:8000/ ! v4l2sink device=/dev/video4

  


  I tried various devices, like /dev/video0, /dev/video1, etc. They all produce '"/dev/videoX" is not a output device', except for video4, which seems to be working at first, but then errors out with :

  


  ERROR : from element /GstPipeline:pipeline0/GstRTSPSrc:rtspsrc0/GstUDPSrc:udpsrc1 : Internal data stream error.
Additional debug info :
gstbasesrc.c(3072) : gst_base_src_loop () : /GstPipeline:pipeline0/GstRTSPSrc:rtspsrc0/GstUDPSrc:udpsrc1 :
streaming stopped, reason not-linked (-1)
Execution ended after 0:00:00.082360368

  


  Any idea what might be going wrong there ?

  


  Edit 2 :

  


  I may have it working with the following sequence of commands :

  


  (on pi) : raspivid -o - -t 0 -n -w 320 -h 240 -fps 30| cvlc -vvv stream :///dev/stdin —sout '#rtpsdp=rtsp ://:8000/' :demux=h264

  


  (on host computer) : ffmpeg -f h264 -i tcp ://10.0.0.47:8000/ -f v4l2 -pix_fmt yuv420p /dev/video0

  


  This doesn't throw any errors, but I'm not 100% sure it's working cause I haven't been able to load the stream in software I'm trying to get the camera feed into yet. I tried testing it with this website tool :

  


  https://test.webrtc.org/

  


  and the tool allows me to select "Dummy Video Device 0x0000", which I'm pretty sure is it, but it then tells me "no video device detected", fails to find any camera in its testing, and then the same Dummy Video Device doesn't show up as an option on subsequent page reloads. So I think there's something wrong about how I'm passing the stream

  


• usb capture device to "cast" stream

  6 juin 2021, par cubesareneat

  im using a raspberry pi with a usb capture device (dmesg -w below)

  


  [ 3825.105250] cx231xx 1-1.4:1.1: New device Geniatech Inc. Video Capture @ 480 Mbps (1f4d:0102) with 6 interfaces
[ 3825.105571] cx231xx 1-1.4:1.1: Identified as Geniatech OTG102 (card=17)
[ 3825.106698] i2c i2c-12: Added multiplexed i2c bus 14
[ 3825.106948] i2c i2c-12: Added multiplexed i2c bus 15
[ 3825.233031] cx25840 11-0044: cx23102 A/V decoder found @ 0x88 (cx231xx #0-0)
[ 3827.270228] cx25840 11-0044: loaded v4l-cx231xx-avcore-01.fw firmware (16382 bytes)
[ 3827.307022] cx231xx 1-1.4:1.1: v4l2 driver version 0.0.3
[ 3827.411911] cx231xx 1-1.4:1.1: Registered video device video0 [v4l2]
[ 3827.412183] cx231xx 1-1.4:1.1: Registered VBI device vbi0
[ 3827.418150] cx231xx 1-1.4:1.1: audio EndPoint Addr 0x83, Alternate settings: 3
[ 3827.418179] cx231xx 1-1.4:1.1: video EndPoint Addr 0x84, Alternate settings: 5
[ 3827.418203] cx231xx 1-1.4:1.1: VBI EndPoint Addr 0x85, Alternate settings: 2
[ 3827.418224] cx231xx 1-1.4:1.1: sliced CC EndPoint Addr 0x86, Alternate settings: 2


  


  i want to stream the audio to "cast" dose this protocol have a more specific name ? its the one that Spotify and YouTube can send audio video to over local network ; little screen with a wifi signal in the bottom left corner.

  


  i am thinking of going into ffmpeg or vlc to stream from usb to some cast program, dose anyone have any suggestions on where to start any key words so im not blindly googling ?
sorry this is so open ended, ill mark it solved with the best answer in like 5 days or when i finish this project ( turntable -> usb audio capture card on pi -> steam to cast protocol -> wifi speakers )