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• What version of ffmpeg is bundled inside electron ?

  7 août 2020, par greghmerrill

  The prebuilt electron binaries for Windows include the file ffmpeg.dll. How can I determine what version of the underlying ffmpeg library is actually compiled to produce this dll ? I need this information to understand what known vulnerabilities (CVE's, etc) might be in a given version of electron via ffmpeg.

  



  As I understand it, the ffmpeg dll itself is taken from https://github.com/electron/nightlies/releases/ when I download my dependencies (I'm using electron-prebuilt-compile). But I'm not getting a clear picture of what the source for that binary is. I think it might be from https://chromium.googlesource.com/chromium/third_party/ffmpeg/ but then I'm not clear on the relationship of that repo with the original ffmpeg repo (e.g. how often are fixes merged from the ffmpeg repo to the chromium third-party repo, etc.)

  



  I tried searching the content of the dll as per cody's suggestion, but no luck :

  



  $ strings ffmpeg.dll  | grep -i ffmp
FFmpeg video codec #1
Huffyuv FFmpeg variant
Not yet implemented in FFmpeg, patches welcome
C:\projects\libchromiumcontent\src\out-x64\static_library\ffmpeg.dll.pdb
ffmpeg.dll


$ strings ffmpeg.dll  | grep -i version
H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2
MPEG-4 part 2 Microsoft variant version 1
MPEG-4 part 2 Microsoft variant version 2
MPEG-4 part 2 Microsoft variant version 3
H.263+ / H.263-1998 / H.263 version 2
On2 VP6 (Flash version)
On2 VP6 (Flash version, with alpha channel)
old standard qpel (autodetected per FOURCC/version)
direct-qpel-blocksize bug (autodetected per FOURCC/version)
edge padding bug (autodetected per FOURCC/version)
strictly conform to a older more strict version of the spec or reference software
minor_version
premiere_version
quicktime_version
Assume this x264 version if no x264 version found in any SEI


  


• How to create a video from images on a .tif format with FFmpeg ?

  18 décembre 2018, par ecjb

  I just discovered FFmpeg : awesome software. After reading this this stackoverflow question I could efficiently create a movie with pictures in a .png format with the following line :

  ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf "fps=25,format=yuv420p" out.mp4

  In an experiment, however, I took high quality pictures on a .tif format and would like to create a movie out of them. I just copied the line above and replaced the name of the files as well as the format .png by .tif but I got a message error saying "This format is not supported". Here is the report :

  [tiff @ 0x7fce5c02a600] This format is not supported (bpp=12, bppcount=1)
  
  Last message repeated 1 times
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [tiff @ 0x7fce5c01bc00] This format is not supported (bpp=12, bppcount=1)
  
  Last message repeated 7 times
  
  Cannot determine format of input stream 0:0 after EOF
  
  Error marking filters as finished
  
  Conversion failed!

  Should I just forget it or is there a workaround with ffmpeg ?

• How do I pre-allocate the memory for libavcodec to write decoded frame data ?

  18 décembre 2018, par codemonkey

  I am trying to decode a video with libav by following the demo code : here

  I need to be able to control where the frame data in pFrame->data[0] is stored. I have tried setting pFrame->data to my own buffer as follows :

  // Determine required buffer size and allocate buffer 
  
  int numBytes = av_image_get_buffer_size(pixFmt, width, height, 1); 
  
  (uint8_t*) dataBuff = (uint8_t*) malloc (numBytes * sizeof(uint8_t)); 
  
  
  
  // Assign buffer to image planes in pFrame
  
  av_image_fill_arrays(frame->data, frame->linesize, dataBuff, pixFmt, width,
  
  height, 1);

  While this does set pFrame->data to be dataBuff (if I print their addresses, they are the same), this call ret = avcodec_receive_frame(pCodecContext, pFrame) to receive the decoded data always writes the data to a different address. It seems to manage its own memory somewhere in the underlying API and ignores the dataBuff that I assigned to pFrame right before.

  So I’m stuck—how can I tell libav to write decoded frame data to memory that I pre-allocate ? I’ve seen people ask similar questions online and in the libav forum but haven’t been able to find an answer.

  Many thanks