Recherche avancée

Sur d’autres sites (9936)

• avcodec/smacker : Use unsigned for prediction values

  26 juin 2020, par Andreas Rheinhardt

  avcodec/smacker : Use unsigned for prediction values
  Up until now, the Smacker decoder has pretended that the prediction
  
  values are signed in code like 'pred[0] += (unsigned)sign_extend(val, 16)'
  
  (the cast has been added to this code later to fix undefined behaviour).
  
  This has been even done in case the PCM format is u8.
  Yet in case of 8/16 bit samples, only the lower 8/16 bit of the predicition
  
  values are ever used, so one can just as well just use unsigned and
  
  remove the sign extensions. This is what this commit does.
  For GCC 9 the time for one call to smka_decode_frame() for the sample from
  
  ticket #2425 decreased from 1709043 to 1693619 decicycles ; for Clang 9
  
  it went up from 1355273 to 1369089 decicycles.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/smacker.c

• ffmpeg drawtext Arabic fonts doesn't render correctly [closed]

  11 février 2024, par Mahmoud Abdellatief

  what i'm trying to achieve :
loop an image into a video and overlay Arabic Text from the Qur'an on it including the text diacritical mark, using a custom font.

  


  example of the text to be rendered :

  


  بِسْمِ ٱللَّهِ ٱلرَّحْمَـٰنِ ٱلرَّحِيمِ


  


  the font used :
https://fonts.qurancomplex.gov.sa/wp02/wp-content/uploads/2024/01/UthmanicHafs_v22.zip

  


  font's unicode module :

  


  Unicode Module 
 
The Research and Development Unit in the Computer Department at King Fahd Glorious Qur’an Printing Complex relied on the unicode system unicode to create (Hafs) font in the Uthmanic Script, because this system is followed globally among computer and systems manufacturing companies in the world.

Unicode organization is a global code group that is used to define all codes and letters used in most of the world's languages and gathered in one code to facilitate the presentation and delivery on information despite of the language used. This global coding uses 1 to 4 bytes (byte = 8 bits) to encode letters, and so far only a third of the number available in Unicode organization to encode the letters of these languages.

Taking into account Hafs font with the Uthmanic Script, which was built entirely on the unicode system. We can explore the basic letters that were formed according to the following figure:

Whereas the font was developed starting from code (0600 ) to code (066FF ) Taking into account there are several encoded letters that haven't been used at all so it was replaces with the code []. The displayed copy above is the one that is been developed from the basic Arabic coding (0600-06FF) which was updated by Unicode organization in 2009.


  


  expected result :
exported video with correctly rendered text using the given font.

  


  actual result :
the text rendered contains only the diacritical marks ( which are the accents on top of the letters ) without the actual letters.


  


  what i tried :
this is my test command which exports just an image for faster results :

  


  Ffmpeg -loop 1  -i "image-2.jpg" -vf "drawtext=text='بِسْمِ ٱللَّهِ ٱلرَّحْمَـٰنِ ٱلرَّحِيمِ':fontsize=124:fontcolor=white:fontfile='UthmanicHafsV22.ttf':x=(w-text_w)/2:y=(h-text_h)/2" -frames:v 1  "output.png"


  


  

  • tried adding ft_load_flags , almost tried all of them

  


  • tried text_shaping=1 , with no success

  


  • tried textfile instead of text

  


  • tried changing the font, any font i try with it always have different problems, either some squares instead of the diacritical mark

  


  


  p.s im having same results on both latest ffmpeg compiled by myself on macos terminal with all required libraries enabled , and also on flutter ffmpeg kit full gpl

  


• How to send AVPacket through a QTcpSocket.write() with all of its data ?

  24 juin 2024, par CottonBuds

  I want to send an AVPacket though a QTcpSocket.write() I tried to cast the avpacket pointer to an char * but it only shows 8 bytes of the avpacket and without the avpacket.data.

  


  

  


  here is my code

  


  void DisplayStreamServer::sendDataToClient(AVPacket* packet) {
    if (client == nullptr) {
        return;
    }


    client->write((char*) packet);
    client->waitForBytesWritten();

    av_packet_unref(packet);
    av_packet_free(&packet);
}


  


  I can see that my packet.data has data inside it using the visual studio memory viewer. but it seems like when i convert the packet to char * the data is not included