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• lavc/aarch64 : port HEVC SIMD idct NEON

  16 janvier 2021, par Reimar Döffinger

  lavc/aarch64 : port HEVC SIMD idct NEON
  Makes SIMD-optimized 8x8 and 16x16 idcts for 8 and 10 bit depth
  
  available on aarch64.
  
  For a UHD HDR (10 bit) sample video these were consuming the most time
  
  and this optimization reduced overall decode time from 19.4s to 16.4s,
  
  approximately 15% speedup.
  
  Test sample was the first 300 frames of "LG 4K HDR Demo - New York.ts",
  
  running on Apple M1.
  Signed-off-by : Josh Dekker <josh@itanimul.li>
  

  • [DH] libavcodec/aarch64/Makefile
  • [DH] libavcodec/aarch64/hevcdsp_idct_neon.S
  • [DH] libavcodec/aarch64/hevcdsp_init_aarch64.c
  • [DH] libavcodec/hevcdsp.c
  • [DH] libavcodec/hevcdsp.h

• command for Php ffmpeg exec

  24 juin 2015, par shilpa shri

  Can anyone please help me with ffmpeg exec command for php , i need converting video file , so that output file should be 640*480 resolution, 128Kbps sound ,output file should be mp4 container video codec H.264 Audio codec AAC

  Currently i am using code
  $a = exec(’"/usr/local/bin/ffmpeg" -y -i "test.mp4" -ab 128k -s 640x480 -vcodec mpeg4 -acodec:a copy "output.mp4" 2>&1 ’, $output, $error) ;

  where output.mp4 file is generated but the video is not clear (very blurred video).
  and the result which displayed on browser shows

  [79] =>     Last message repeated 391 times
  
  [80] => frame= 5159 fps=723 q=24.8 size=   12857kB time=00:03:26.91 bitrate= 509.0kbits/s dup=4591 drop=0    
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [81] =>     Last message repeated 359 times
  
  [82] => frame= 5627 fps=739 q=31.0 Lsize=   14071kB time=00:03:45.16 bitrate= 511.9kbits/s dup=5009 drop=0
  
  [83] => video:8650kB audio:5277kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.030902%
  
  [84] => Conversion failed!

  Input file was 82.21mb
  output file was 13.74mb

• Decoding AAC to PCM with ffmpeg results in noise

  18 octobre 2022, par userDtrm

  I have a .mp4 file generated with ffmpeg as follows.

  


  


  ffmpeg -y -i video_extended.mp4 -itsoffset 00:00:04.00 -i output5-1.wav -map 0:0 -map 1:0 -c:v copy -c:a aac -ac 6 -ar 48000 -b:a 128k -async 1 mixed.mp4

  


  


  Playing mixed.mp4 file with ffplay is fine and there is no impact to the sound quality. Below is the output I get from ffplay when using the command ffplay -i  mixed.mp4

  


  > Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
> 'mixed_h264_aac_512k_async_qp0_all_I.mp4':   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf58.76.100   Duration: 00:00:16.02, start: 0.000000, bitrate: 49136 kb/s   Stream #0:0[0x1](und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuv422p10le(progressive),
> 1920x1080, 65409 kb/s, 59.94 fps, 59.94 tbr, 11988 tbn (default)
>     Metadata:
>       handler_name    : VideoHandler
>       vendor_id       : [0][0][0][0]   Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 71 kb/s (default)
>     Metadata:
>       handler_name    : SoundHandler
>       vendor_id       : [0][0][0][0] Switch subtitle stream from #-1 to #-1 vq= 1606KB sq=    0B f=0/0


  


  Then, I decode the mixed.mp4 file back to raw PCM using the following command.

  


  


  ffmpeg -i mixed.mp4 -vn -acodec pcm_s16le -f s16le -ar 48000 -ac 6 raw_audio.pcm

  


  


  However, this raw_audio.pcm contains a lot of noise and ffplay output shows the following output

  


  [s16le @ 0x7f7490000c80] Estimating duration from bitrate, this may be inaccurate
Input #0, s16le, from 'separated_audio_s16.pcm':
  Duration: 00:00:16.02, bitrate: 4607 kb/s
  Stream #0:0: Audio: pcm_s16le, 48000 Hz, 6 channels, s16, 4608 kb/s
[pcm_s16le @ 0x7f749002b940] Multiple frames in a packet.
[pcm_s16le @ 0x7f749002b940] Invalid PCM packet, data has size 8 but at least a size of 12 was expected
    Last message repeated 32 times
[pcm_s16le @ 0x7f749002b940] Invalid PCM packet, data has size 8 but at least a size of 12 was expected
    Last message repeated 11 times
Switch subtitle stream from #-1 to #-1 vq=    0KB sq=    0B f=0/0   
[pcm_s16le @ 0x7f749002b940] Invalid PCM packet, data has size 8 but at least a size of 12 was expected
    Last message repeated 11 times
[pcm_s16le @ 0x7f749002b940] Invalid PCM packet, data has size 8 but at least a size of 12 was expected
    Last message repeated 11 times
[pcm_s16le @ 0x7f749002b940] Invalid PCM packet, data has size 8 but at least a size of 12 was expected


  


  Can someone please explain the issue here ? Note that the ffplay command that works correctly for mixed.mp4 shows fltp as the audio format, whereas when playing the raw_audio.pcm file, it is seen as s16.

  


  Is this a resampling issue in ffmpeg, and how can I rectify this ?

  


  I’m using ffmpeg and ffplay versions 5.0.1 in a Fedora 36 system.

  


  Thank you.