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• Is there a possibility to automatically render .json data into a video file ? [closed]

  3 septembre 2020, par chipsys

  I have a .json document from a dash cam which includes date, time, velocity, longitude and latitude for each frame.

  


  My goal is just to write the text on the lower third of each frame. Future projects might animate a speedometer and implement open street map.

  


  I have looked at ffmpeg but haven’t found a way to implement it yet.

  


  If you have the slightest idea on how to implement this please leave a response or guide me in the right direction.

  


  Thank you.

  


• ffmpeg send intra and gop over a traditionnal tcp (or udp) server

  27 décembre 2015, par the-owner

  The Problem :
  I want to stream a continuous sequence of bitmaps (a video if stuck).
  I want to send the stream over a QTcpSocket/Server (or a QUdpServer why not, or a traditional tcp/udp server), and with the help of ffmpeg librarie.

  Context and Conditions :
  I code in C++, under msvc2013 win-32, QT-IDE, ffmpeg dev 2.8.3.
  We start with a bitmap which is a raw format, a result from GDI+ that I have gotten.
  For very low client connection, so I will use a light video format compression MPEG-1.
  I already have a TCP-Server (QTcpServer), so my goal is to not rebuild another Server for it ...

  Potential algorithm ? :
  I have thought more on the encoding question than the procole one, assume that the protocol could be good.
  It is the very first time that I do it, I don’t want to enroll into something impossible, and obviously I want your insight about this problem which I think since last month (which I have not found a good answer on internet). So, below the outlines of the algorithm that I have imagined :

  Server Side :

  1. I convert the first BMP to YUV format thanks to sws_scale (), we name it P in the following (ffmpeg - libswscale)
  2. I (MPEG1-)encode the picture P (with avcodec_encode_video2()) I get the datas encoded
  3. I serialize the AVFrame/AVpicture P (maybe we will do this step just once)
  4. In the same time I push the datas into a QByteArray (or a simple byte array ?)
  5. I compress P (maybe with QCompress why not)
  6. I send it to the clients.
  7. If the step 6 goes well : we return to number 1 if the next image is a modulus of k, it will be an Intra otherwise a GOP
  8. Otherwise, I wait ? Or I can take into account the lost frame within the code, and I could jump it ? (Inside these question there are questions of server protocols)

  Client Side (summarized)

  1. We get the datas (new Intra or GOP),
  2. We check the error function on the datas received with respect to the other datas received
  3. If the error function return :
  4. "The Error is OK with this new Intra/GOP received" we start decoding them with ffmpeg, and we display the next image of the livestream.
  5. Otherwise, error is not OK, we take the error into account ... (it is not my main problem here)

  Questions :

  It is a solution that I imagined, If the question of server/client protocol are solved, my algorithm is it viable in order to do a livestream ? Could it work ? Is there a better solution ? (another more simpler algorithm or another librarie than ffmpeg for example or something else ?) a link ? Of course critics on my server protocol are welcome.

  I remind, it is just the outlines.

• libx264 fails on HTTP Live Streaming (FFmpeg)

  12 juillet 2016, par shintaroid

  I want to live stream with HTTP Live Streaming, but I have problem with libx264 or maybe something other.

  My hardware and software environment :

  • Macbook Pro
  • VirtualBox with Ubuntu 16.04
  • Nginx and FFmpeg (in Ubuntu)

  I am able to stream a static video file (in Ubuntu with Nginx and FFmpeg).
  The FFmpeg command is as following :

  $ffmpeg -i /my/sample/video.mp4 -codec:v libx264 -f hls /output/file.m3u8

  But when it comes to webcam (live streaming), Mac OS Safari fails to open the stream. I used the following command :

  $ffmpeg -i /dev/video0 -codec:v libx264 -f hls /output/file.m3u8

  I guess it’s the problem of libx264 because when I use mpeg2video encoder, Mac OS Safari indeed can play the stream :

  $ffmpeg -i /dev/video0 -codec:v mpeg2video -f hls /output/file.m3u8

  I know there is a library called video4linux2, should I use video4linux2 for capturing my webcam ? But I don’t know the appropriate FFmpeg command for HTTP Live Streaming (I tried FFserver but there is error something like cannot rename hls)

  anyone shed some light on my problem ?