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• ffmpeg how add header info into pcm ?

  23 septembre 2021, par Zheng Xiaodong

  I use this cmd convert s16le to pcmu8, but will lost header info.

  


  ffmpeg -i s16le.wav -f u8 pcmu8.wav
ffmpeg -i pcmu8.wav
# pcmu8.wav: Invalid data found when processing input


  


  I want known, how add this header info into pcmu8.wav ?

  


  It should be this :

  


  ffmpeg -i pcmu8.wav
#Input #0, wav, from 'pcmu8.wav':
#  Duration: 00:13:39.20, bitrate: 64 kb/s
#  Stream #0:0: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 8000 Hz, mono, u8, 64 kb/s


  


• ffmpeg libav : Any way to set stream info in an input format instead of searching for it ?

  26 octobre 2019, par Tricky Widget

  I’m writing a player for an RTMP stream using the ffmpeg API. I know the usual way to get the stream info into an input format is with avformat_find_stream_info. And that works. However, because it’s RTMP it takes a long time for it to scan enough of the stream to pick up the info. I’ve played with max_analyze_duration and probesize and it’s a bit better, but it still takes 10-15 seconds to load. That’s way too long for my application.

  But I’m the one making the stream on the other end, so I know exactly what’s in it. It seems like it would make more sense for me to tell the input format what the stream info is rather than asking it to search for it. But I can’t find any examples of this, and my attempts to use avformat_new_stream with an input format aren’t working.

  Does anyone know if this is possible ? And if so, could you point me in the direction of how ?

  Thanks !

• arm : vp9itxfm16 : Do a simpler half/quarter idct16/idct32 when possible

  24 février 2017, par Martin Storsjö

  arm : vp9itxfm16 : Do a simpler half/quarter idct16/idct32 when possible
  This work is sponsored by, and copyright, Google.
  This avoids loading and calculating coefficients that we know will
  
  be zero, and avoids filling the temp buffer with zeros in places
  
  where we know the second pass won’t read.
  This gives a pretty substantial speedup for the smaller subpartitions.
  The code size increases from 14516 bytes to 22484 bytes.
  The idct16/32_end macros are moved above the individual functions ; the
  
  instructions themselves are unchanged, but since new functions are added
  
  at the same place where the code is moved from, the diff looks rather
  
  messy.
  Before :                                 Cortex A7       A8       A9      A53
  
  vp9_inv_dct_dct_16x16_sub1_add_10_neon :     454.0    270.7    418.5    295.4
  
  vp9_inv_dct_dct_16x16_sub2_add_10_neon :    3840.2   3244.8   3700.1   2337.9
  
  vp9_inv_dct_dct_16x16_sub4_add_10_neon :    4212.5   3575.4   3996.9   2571.6
  
  vp9_inv_dct_dct_16x16_sub8_add_10_neon :    5174.4   4270.5   4615.5   3031.9
  
  vp9_inv_dct_dct_16x16_sub12_add_10_neon :   5676.0   4908.5   5226.5   3491.3
  
  vp9_inv_dct_dct_16x16_sub16_add_10_neon :   6403.9   5589.0   5839.8   3948.5
  
  vp9_inv_dct_dct_32x32_sub1_add_10_neon :    1710.7    944.7   1582.1   1045.4
  
  vp9_inv_dct_dct_32x32_sub2_add_10_neon :   21040.7  16706.1  18687.7  13193.1
  
  vp9_inv_dct_dct_32x32_sub4_add_10_neon :   22197.7  18282.7  19577.5  13918.6
  
  vp9_inv_dct_dct_32x32_sub8_add_10_neon :   24511.5  20911.5  21472.5  15367.5
  
  vp9_inv_dct_dct_32x32_sub12_add_10_neon :  26939.5  24264.3  23239.1  16830.3
  
  vp9_inv_dct_dct_32x32_sub16_add_10_neon :  29419.5  26845.1  25020.6  18259.9
  
  vp9_inv_dct_dct_32x32_sub20_add_10_neon :  31146.4  29633.5  26803.3  19721.7
  
  vp9_inv_dct_dct_32x32_sub24_add_10_neon :  33376.3  32507.8  28642.4  21174.2
  
  vp9_inv_dct_dct_32x32_sub28_add_10_neon :  35629.4  35439.6  30416.5  22625.7
  
  vp9_inv_dct_dct_32x32_sub32_add_10_neon :  37269.9  37914.9  32271.9  24078.9
  After :
  
  vp9_inv_dct_dct_16x16_sub1_add_10_neon :     454.0    276.0    418.5    295.1
  
  vp9_inv_dct_dct_16x16_sub2_add_10_neon :    2336.2   1886.0   2251.0   1458.6
  
  vp9_inv_dct_dct_16x16_sub4_add_10_neon :    2531.0   2054.7   2402.8   1591.1
  
  vp9_inv_dct_dct_16x16_sub8_add_10_neon :    3848.6   3491.1   3845.7   2554.8
  
  vp9_inv_dct_dct_16x16_sub12_add_10_neon :   5703.8   4831.6   5230.8   3493.4
  
  vp9_inv_dct_dct_16x16_sub16_add_10_neon :   6399.5   5567.0   5832.4   3951.5
  
  vp9_inv_dct_dct_32x32_sub1_add_10_neon :    1722.1    938.5   1577.3   1044.5
  
  vp9_inv_dct_dct_32x32_sub2_add_10_neon :   15003.5  11576.8  13105.8   9602.2
  
  vp9_inv_dct_dct_32x32_sub4_add_10_neon :   15768.5  12677.2  13726.0  10138.1
  
  vp9_inv_dct_dct_32x32_sub8_add_10_neon :   17278.8  14825.4  14907.5  11185.7
  
  vp9_inv_dct_dct_32x32_sub12_add_10_neon :  22335.7  21544.5  20379.5  15019.8
  
  vp9_inv_dct_dct_32x32_sub16_add_10_neon :  24165.6  23881.7  21938.6  16308.2
  
  vp9_inv_dct_dct_32x32_sub20_add_10_neon :  31082.2  30860.9  26835.3  19711.3
  
  vp9_inv_dct_dct_32x32_sub24_add_10_neon :  33102.6  31922.8  28638.3  21161.0
  
  vp9_inv_dct_dct_32x32_sub28_add_10_neon :  35104.9  34867.5  30411.7  22621.2
  
  vp9_inv_dct_dct_32x32_sub32_add_10_neon :  37438.1  39103.4  32217.8  24067.6
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/arm/vp9itxfm_16bpp_neon.S