Newest 'x264' Questions - Stack Overflow

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• Cannot find yasm even though I have installed it

  20 juin 2016, par zhen lee

  I got a strange problem. I tried to install x264. When run sudo ./configure --enable-shared, it gave:

  Found no assembler Minimum version is yasm-0.7.0 If you really want to compile without asm, configure with --disable-asm.

  But I already installed yasm-0.7.0 ,to prove that ,i run yasm --version,it gave:

  *yasm 0.7.0.2066 Compiled on May 8 2012. Copyright (c) 2001-2008 Peter Johnson and other Yasm developers. Run yasm --license for licensing overview and summary.*

  I install yasm to /usr/local/yasm, Why can it not find yasm?

• What's the relationship between AVPacket in FFMpeg and H.264 NAL Uint ?

  8 juin 2016, par Ello

  I use FFMpeg's api to encode images to H.264 stream, the code is like this encode code. When I called the function avcodec_encode_video2 I got one AVPacket's data, then I saved it to file. I use several images to get several files for test. Based on the startcode 00 00 00 01 or 00 00 01, I found that the 1st and 2nd files' data both contain several H.264 NAL Uints. But start from the third file, I can't found the startcode. Like followed image.

  I feel confused. Base on the FFMpeg's code I think one AVPacket's data should contain at least one NAL Uint, but the result is unexpected. Is that means one NAL Uint may be divided to two AVPackets' data? What's the relationship between AVPacket and H.264 NAL Uint?

• how to wide gamut ,convert from 8bit to 10bit

  7 juin 2016, par zhx
  1. I know that the video we watched on the tv is compressed.The range of the gamut will be narrow.I want to know if there is a magical way can achieve the extending.Dolby claimd the Perceptual Quantizer(PQ)EOTE .there is two function Eg.the Perceptual Quantizer(PQ)EOTE this quetion is like the way to convert bt709 to bt2020.
  2. I want to convert 8bit to 10bit like the x264. the computer suports only the 8 |16|32 bit.so which kinde of data type to save the 10bit .someone said that we use the 16bit ,the last six bit we use zero to fill.is that right ,i dont think thats a good way.many thanks

• Get frame type for specific frame using ffmpeg

  1er juin 2016, par Damnesia

  I need to get the frame type (I/B/P) of a specific frame number for an x264 encoded movie.

  How do I do this using ffmpeg/ffprobe? I'm open to other solutions as well.

• Piping from ffmpeg to x264 not working

  23 mai 2016, par JiZhaku_San

  I want to encode video file to AVC-I50. I have a vbs script.

  set objShell = WScript.CreateObject ("WScript.Shell")
  
  objShell.run "cmd.exe /C Processors\ffmpeg.exe -i  """ & PathToInputFile & """ -f lavfi 
  -i aevalsrc=0 -loglevel quiet -shortest -filter_complex 
  ""[0:1]pan=1|c0=c0[a1],[0:1]pan=1|c0=c1[a2],[0:1]pan=1|c0=c2[a3],[0:1]pan=1|c0=c3[a4]""  
  -map ""[a1]"" -c:a pcm_s24le -ar 48000 -y -t """ & duration & """ tmp\01.wav 
  -map ""[a2]"" -c:a pcm_s24le -ar 48000 -y -t """ & duration & """ tmp\02.wav 
  -map ""[a3]"" -c:a pcm_s24le -ar 48000 -y -t """ & duration & """ tmp\03.wav 
  -map ""[a4]"" -c:a pcm_s24le -ar 48000 -y -t """ & duration & """ tmp\04.wav  
  -map 0:v -c:v rawvideo -strict -1 -vf format=yuv420p10,fps=fps=30000/1001 
  -s 1440x1080 -q:v 0 -an -f yuv4mpegpipe pipe:output.y4m | Processors\x264.exe - 
  --demuxer y4m  --frames 1077 --interlaced --tff  --output-csp i420 --no-cabac 
  --force-cfr --keyint 1 --colorprim bt709 --transfer bt709 --tune psnr --sar 1:1 
  --nal-hrd cbr --pic-struct --videoformat component  --vbv-maxrate 50000 --vbv-bufsize 2000 
  --colormatrix bt709 --bitrate 50000 --avcintra-class 50 --output tmp\Result.h264 ", 1, true
  

  When I try to run in cmd this vbs file, it is working. But when I try to run it in C# as Process - it doesn't. Btw. when I try to run it as plain command in cmd it sais that "-" is not an input for x264.