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• aacdec : move from scalefactor ranged arrays to flat arrays

  14 mai 2024, par Lynne

  aacdec : move from scalefactor ranged arrays to flat arrays
  AAC uses an unconventional system to send scalefactors
  
  (the volume+quantization value for each band).
  
  Each window is split into either 1 or 8 blocks (long vs short),
  
  and transformed separately from one another, with the coefficients
  
  for each being also completely independent. The scalefactors
  
  slightly increase from 64 (long) to 128 (short) to accomodate
  
  better per-block-per-band volume for each window.
  To reduce overhead, the codec signals scalefactor sizes in an obtuse way,
  
  where each group's scalefactor types are sent via a variable length decoding,
  
  with a range.
  
  But our decoder was written in a way where those ranges were carried through
  
  the entire decoder, and to actually read them you had to use the range.
  Instead of having a dedicated array with a range for each scalefactor,
  
  just let the decoder directly index each scalefactor.
  This also switches the form of quantized scalefactors to the format
  
  the spec uses, where for intensity stereo and regular, scalefactors
  
  are stored in a scalefactor - 100 form, rather than as-is.
  USAC gets rid of the complex scalefactor handling. This commit permits
  
  for code sharing between both.
  

  • [DH] libavcodec/aac/aacdec.c
  • [DH] libavcodec/aac/aacdec.h
  • [DH] libavcodec/aac/aacdec_dsp_template.c

• Error and understanding issue : using ffmpeg to real time publish FLV file to Red5 and real time download FLV from Red5

  29 août 2014, par kajarigd

  OS : Windows 8, RTMP Server : Red5, Video File format : FLV, I want to : Read/Write FLV from and to Red5 by live streaming.

  To publish FLV file from local I am using this command at Command Line :

  ffmpeg -re -i input.flv -acodec copy -vcodec copy -f flv rtmp://ocalhost/oflaDemo/streams

  My understanding : This command will upload input.flv to the server location C :\Program Files\red5\webapps\oflaDemo\streams. So, after the command is done running, I expect in this server location a new file input.flv will be created. Is this correct ?

  When I am running this command I am getting the following error and no file is getting created on the server side :

  [flv @ 03c6a660] Failed to update header with correct duration.
  
  [flv @ 03c6a660] Failed to update header with correct filesize.
  
  frame= 1567 fps= 24 q=-1.0 Lsize=    3064kB time=00:01:05.43 bitrate= 383.6kbits
  
  /s
  
  video:2232kB audio:767kB subtitle:0kB other streams:0kB global headers:0kB muxin
  
  g overhead: 2.183349%

  Can you help me understand what I am doing wrong ? What should be correct command in this case to achieve what I want ?

  Now, I am using the following command to livestream read a FLV file from the server into my local :

  ffmpeg -re -i rtmp://localhost/oflaDemo/streams/hobbit_vp6.flv -c copy dump.flv

  My understanding : File hobbit_vp6.flv will be downloaded into my local directory and will get saved as dump.flv. And this will be live streaming. This will be like, recording a video stream from the server. Is this correct ?

  When I am running this command I am getting the following error and no file is getting created on the local :

  Closing connection: NetStream.Play.StreamNotFound rtmp://localhost/oflaDemo/streams/hobbit_vp6.flv: Unknown error occurred

  Can you help me understand what I am doing wrong ? What should be correct command in this case to achieve what I want ?

• Revision b208439b5a : Merge "Fix best ref frame rd cost update in sub8x8 non-RD mode search"

  7 janvier 2015, par Jingning Han

  Merge "Fix best ref frame rd cost update in sub8x8 non-RD mode search"