Newest 'libx264' Questions - Stack Overflow

Les articles publiés sur le site

• VLC huge buffering times over rtp for local H264 stream

  15 mars 2022, par mike

  I'm outputting an H264 stream, encoded by my application using ffmpeg. I can display it using ffplay, but when trying to view the stream in VLC, I only get the first frame, or it looks like that's the case.

  The messages output shows that it is "buffering", taking around a minute to get to 100% when the frame updates. When using ffplay, the latency is about 50-100ms at worst.

  I am sending to rtp://127.0.0.1:6666?pkt_size=1316 with the format rtp_mpegts. I am new to this and it's highly likely I haven't set the frame up completely correctly. The process is (minus declarations and error checking)

  codec_name = "libx264";
  codec = avcodec_find_encoder_by_name(codec_name.c_str());
  context = avcodec_alloc_context3(codec);
  pkt = av_packet_alloc();
  context->bit_rate = 5 * Mega;
  context->width = info.DisplayWidth;
  context->height = info.DisplayHeight;
  context->time_base = { 1, FPS };
  context->framerate = { FPS, 1 };
  context->gop_size = 100;
  context->max_b_frames = 1;            
  context->pix_fmt = AV_PIX_FMT_YUV420P;
  if (codec->id == AV_CODEC_ID_H264)
              {
                  check_ret("set option: preset", av_opt_set(context->priv_data, "preset", "fast", 0));
                  check_ret("set option: tune", av_opt_set(context->priv_data, "tune", "zerolatency", 0));
                  check_ret("set option: profile", av_opt_set(context->priv_data, "profile", "baseline", 0));                
              }
  check_ret("open codec", avcodec_open2(context, codec, NULL));
  
  // setup the stream 
  fmt = (AVOutputFormat*)av_guess_format("rtp_mpegts", NULL, NULL);
  
  avformat_alloc_output_context2(&avfctx, fmt, fmt->name,
              "rtp://127.0.0.1:6666?pkt_size=1316"); 
          
  avio_open(&avfctx->pb, avfctx->url, AVIO_FLAG_WRITE);
  AVStream* stream = avformat_new_stream(avfctx, codec);
  avcodec_parameters_from_context(stream->codecpar, context);
  stream->time_base.num = 1;
  stream->time_base.den = FPS;
  avformat_write_header(avfctx, NULL);
  
  // then the encoding (in an output loop)
  
  yuvFrame->pts = i++; // i is incremented every frame
  avcodec_send_frame(enc_ctx, yuvFrame);
   while (ret >= 0) {
    ret = avcodec_receive_packet(enc_ctx, pkt);          
    //ret = av_interleaved_write_frame(avfctx, pkt); was using this, don't seem to need it
    ret = av_write_frame(avfctx, pkt);
    av_packet_unref(pkt);
  }
  

  The VLC output looks like this:

  main debug: using hw decoder module "d3d11va"
  avcodec info: Using D3D11VA (NVIDIA GeForce RTX 2080 Super with Max-Q Design, vendor 10de(NVIDIA), device 1e93, revision a1) for hardware decoding
  qt debug: Logical video size: 1280x720
  main debug: resized to 1280x720
  main debug: VoutDisplayEvent 'resize' 1280x720
  main debug: Received first picture
  main debug: Buffering 1%
  main debug: Buffering 2%
  main debug: Buffering 3%
  main debug: auto hiding mouse cursor
  main debug: Buffering 4%
  main debug: Buffering 5%
  main debug: Buffering 6%
  main debug: Buffering 7%
  main debug: Buffering 8%
  main debug: Buffering 9%
  main debug: Buffering 10%
  main debug: auto hiding mouse cursor
  main debug: Buffering 11%
  rtp warning: 1 packet(s) lost
  rtp warning: 1 packet(s) lost
  rtp warning: 1 packet(s) lost
  ts warning: discontinuity received 0x3 instead of 0xd (pid=256)
  ts warning: discontinuity received 0x5 instead of 0xf (pid=256)
  ts warning: discontinuity received 0x1 instead of 0xb (pid=256)
  main debug: Buffering 12%
  main debug: Buffering 13%
  main debug: Buffering 14%
  main debug: Buffering 15%
  main debug: Buffering 16%
  main debug: Buffering 17%
  main debug: Buffering 18%
  main debug: auto hiding mouse cursor
  main debug: Buffering 19%
  main debug: Buffering 20%
  

• Access to motion vector's (x, y) coordinate while using libx264 encoder

  8 mars 2022, par Rockland

  I want to know if it is possible to get motion vectors values (x, y) somehwhere in the enconding process while using libx264 encoder.

  I have a project where I need to modify motion vectors values during encoding process. What I want to do concretly is for exemple : motion_x = motion_x + 1 and/or motion_y = motion_y -1

  I want to know if it is possible to get motion vectors values (x, y) somehwhere in the enconding process while using libx264 encoder.

  I have a project where I need to modify motion vectors values during encoding process. What I want to do concretly is for exemple : motion_x = motion_x + 1 and/or motion_y = motion_y -1

  I know that it is possible to do that while using the standards ffmpeg encoders. Precisily in the function static int encode_picture(MpegEncContext *s, int picture_number) in the file mpegvideo_enc.c located in the ffmpeg's libavcodec directory, we can get and modify motion vector's values in the struct MpegEncContext (->current_picture.motion_val). When I use libx264 encoder, this function is not called so I don't know where and how to do that.

  Your help will be verry appreciated.

• FFMPEG : Convert WebM VP8/VP9 multi-resolution video to MP4 (H.264)

  28 janvier 2022, par thedeadalive

  I have been trying to convert a multi-resolution WebM video ( VP9/VP8/H.264 ) (1280 x 1080 till the half, thereafter 1080 x 1280) to MP4 container with H.264 encoding for video.

  When transcoded with FFMPEG is locking into the frame size it's encountering at the start of the video (1280 x 1080 in this case) when transcoded with libvpx (for VP8 and VP9) and libx264 (for H264).

  The only instance i could get it right was when the Input WebM was having H.264 video and opus Audio, and ffmpeg was instructed to just copy the video stream and trans-code the Audio to aac only.

  Is there way in make ffmpeg support multi-resolution video transcoding?

  How to generate a sample video: On a Chrome or Firefox (on a device that supports auto rotation and has different resolution on portrait and landscape) that supports mediaRecorder API goto this link: https://webrtc.github.io/samples/src/content/getusermedia/record/ , start recording a video , while recording the video, change orientation, stop recording and download the video. file)

  Discussion Reference: https://groups.google.com/a/webmproject.org/forum/#!topic/webm-discuss/IgumDyMAHY0

• Getting Error message Unknown encoder 'libx264' , any help appreciated

  16 janvier 2022, par Alex.Foster

  I am trying to compress videos files to a target size within python using ffmpeg-python for an A level project as part of my coursework, I keep getting this error saying it doesn't know the encoder. Not sure what I'm meant to do as this is literally an entirely new space to me. Am I meant to have installed the codec or something, or is there an alternative I can use?

  import os, ffmpeg
  ##import section:this part is where I import all of the modules I will use
  import  tkinter
  import shutil
  from tkinter import filedialog
  import os
  
  
  def fileSelect():                                                                           #start of fileSelect function
      global startingLocation                                                                 #declares startingLocation as global variable
      global originalName                                                                     #declares originalName as global variable
      global fileType                                                                         #declares fileType as global variable
      startingLocation = filedialog.askopenfilename(initialdir="/", title="Select file",      #tkinter function that opens file explorer, lets user select file saves the file path as a variable
                      filetypes=(("video files", "*.mp4"),("images", "*.jpg*")))
      originalName = os.path.basename(startingLocation)                                       #os function that gets the actaul file name from the path string
      print (originalName)                                                                    #print statement to check if originalName has been found
      fileType = startingLocation.split('.')                                                  #splits original name where any full stop in found and saves array as variable
      fileType = fileType[-1]                                                                 #changes variable to have the str value of the final item in the array; the file type
      fileType = '.' + fileType                                                               #adds fullstop to the start of the file type so i dont have to repeatedly do it
      print (fileType)                                                                        #print statement to check file type is found correctly
  
  def outputSelect():                                                                         #start of outputSelect function
       global outputLocation                                                                  #declares outputLocation as global variable
       outputLocation = filedialog.askdirectory(initialdir="/", title="Select folder")        #tkinter function that opens file explorer, lets the user select of folder as saves the folder path as a variable
  
  def fileNewName():                                                                          #start of fileNewName function
      global customName                                                                       #declares customName as global variable
      customName = input("Enter the end name of your file")                                   #simple code assigning user input to the custom name vairable
      customName = customName + fileType                                                      #add the fileType onto the end of the custom name
  
  def compress():                                                                             #start of compress function
      fileSelect()                                                                            #calls the fileSelect function
      outputSelect()                                                                          #calls the outputSelect function
      fileNewName()
      global src
      global dst                                                                           #calls the fileNewName function
      src = startingLocation                                                                  #assigns startingLocation str as src, so the shutil module is able to use it in a cleaner way
      dst = outputLocation                                                                    #assigns outputLocation dst as src, so the shutil module is able to use it in a cleaner way
      shutil.copy(src, dst)                                                                   #shutil command that copies the file from src to dst
      src = outputLocation + '/' + originalName                                               #reassigns src as the location of the file copy
      dst = outputLocation + '/' + customName                                                 #reassigns dst as the location of the file copy but with a new name
      shutil.move(src,dst)
  
  
  def compress_video(video_full_path, output_file_name, target_size):
      # Reference: https://en.wikipedia.org/wiki/Bit_rate#Encoding_bit_rate
      min_audio_bitrate = 32000
      max_audio_bitrate = 256000
  
      probe = ffmpeg.probe(video_full_path)
      # Video duration, in s.
      duration = float(probe['format']['duration'])
      # Audio bitrate, in bps.
      audio_bitrate = float(next((s for s in probe['streams'] if s['codec_type'] == 'audio'), None)['bit_rate'])
      # Target total bitrate, in bps.
      target_total_bitrate = (target_size * 1024 * 8) / (1.073741824 * duration)
  
      # Target audio bitrate, in bps
      if 10 * audio_bitrate > target_total_bitrate:
          audio_bitrate = target_total_bitrate / 10
          if audio_bitrate < min_audio_bitrate < target_total_bitrate:
              audio_bitrate = min_audio_bitrate
          elif audio_bitrate > max_audio_bitrate:
              audio_bitrate = max_audio_bitrate
      # Target video bitrate, in bps.
      video_bitrate = target_total_bitrate - audio_bitrate
  
      i = ffmpeg.input(video_full_path)
      ffmpeg.output(i, os.devnull,
                    **{'c:v': 'libx264', 'b:v': video_bitrate, 'pass': 1, 'f': 'mp4'}
                    ).overwrite_output().run()
      ffmpeg.output(i, output_file_name,
                    **{'c:v': 'libx264', 'b:v': video_bitrate, 'pass': 2, 'c:a': 'aac', 'b:a': audio_bitrate}
                    ).overwrite_output().run()
  
  compress()
  compress_video(dst, outputLocation, 3 * 1000)
  

• How to resolve "ERROR : libx264 not found" ?

  13 janvier 2022, par davidvarghese

  I needed to install ffmpeg with libx264 support for enabling H.264 encoding . I installed libx264 successfully using the below script with toolchains available in android-ndk-r9d .

   #!/bin/bash
   NDK=~/android-ndk-r9d
   SYSROOT=$NDK/platforms/android-8/arch-arm/
   TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64
   function build_one
   {
   ./configure \
   --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
   --sysroot="$SYSROOT" \
   --host=arm-linux \
   --enable-pic \
   --enable-shared \
   --disable-cli
   make clean
   make
   make install
   }
   build_one 
  

  Now I wanted to build ffmpeg with libx264 support . I used the below script with --enable-libx264 , --enable-nonfree , --enable-gpl options as in the below script .

  #!/bin/bash
  NDK=~/android-ndk-r9d
  SYSROOT=$NDK/platforms/android-8/arch-arm/
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64
  function build_one
  {
  ./configure \
  --prefix=$PREFIX \
  --enable-shared \
  --enable-nonfree \
  --enable-gpl \
  --enable-libx264 \
  --disable-doc \
  --disable-ffmpeg \
  --disable-ffplay \
  --disable-ffprobe \
  --disable-ffserver \
  --disable-avdevice \
  --disable-doc \
  --disable-symver \
  --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  --target-os=linux \
  --arch=arm \
  --enable-cross-compile \
  --sysroot=$SYSROOT \
  --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
  --extra-ldflags="$ADDI_LDFLAGS" \
  $ADDITIONAL_CONFIGURE_FLAG
  make clean
  make
  make install
  }
  CPU=arm
  PREFIX=$(pwd)/android/$CPU
  ADDI_CFLAGS="-marm"
  build_one
  

  But when I run the script I'm getting error "ERROR: libx264 not found" .

  I suppose ffmpeg is not able to figure out the installed location of libx264 . After libx264 installation I have libx264.so file in /usr/local/lib executable at /usr/local/bin and header files at /usr/local/include directories .

  What all changes do I need to make to the ffmpeg build script in-order to make it detect libx264?

  Note : I am using Ubuntu 12.04(64 bit) for cross compiling .