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• Writing H.264 RTP stream data to a container file

  2 avril 2018, par Kamal

  In a call, I receive RTP packets (h264 payload). I am trying to depacketize it and write it to a container file like mkv or mp4 using ffmpeg. However the output file is not playing. I am following below steps, please let me know whats wrong here.

  1. Got RTP packet
  2. Removed RTP header 12 bytes
  3. Read one more byte and calculated F, NRI & Type value. Type value comes to 1 most of the time, sometime it is 5 also.
  4. Since type is in between 1 & 23, it is of type single NAL unit.
  5. Allocates a buffer say BUF.
  6. Writes first 3 byte as 0x00 0x00 0x01.
  7. Then copy from video payload + 1 offset (since we have read 1 byte as described in point #3) to BUF
  8. Use this BUF to prepare avpacket and write this to output file using AV_Write_* API of ffmpeg. This part I have done correctly as it works fine for me in case of vp8 codec.
  9. Get the output file.
  10. However this file is not playing in ffmpeg.

  Please let me know of my approach is correct.

  I have observed sometimes group of packets coming with marker bit as 0, with same RTP timestamp. Do I need to concatenate such group of packets and write as single NALU, or each packet I should write as single NALU to output file.

• avformat/hlsenc : add var_stream_map DEFAULT field status parameter

  23 janvier 2019, par Steven Liu

  avformat/hlsenc : add var_stream_map DEFAULT field status parameter
  use a:0,agroup:aud_low,default:Yes a:1,agroup:aud_low,
  
      a:2,agroup:aud_high,default:Yes a:3, agroup:aud_high,
  
      v:0,agroup:aud_low v:1,agroup:aud_high
  
      create master m3u8 list.
  result :
  
  EXTM3U
  
  EXT-X-VERSION:3
  
  EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_low",NAME="audio_0",DEFAULT=YES,URI="out_0.m3u8"
  
  EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_low",NAME="audio_1",DEFAULT=NO,URI="out_1.m3u8"
  
  EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_high",NAME="audio_2",DEFAULT=YES,URI="out_2.m3u8"
  
  EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_high",NAME="audio_3",DEFAULT=NO,URI="out_3.m3u8"
  
  EXT-X-STREAM-INF:BANDWIDTH=1170400,RESOLUTION=640x480,CODECS="avc1.64001e,mp4a.40.2",AUDIO="group_aud_low"
  
  out_4.m3u8
  
  EXT-X-STREAM-INF:BANDWIDTH=3440800,RESOLUTION=640x480,CODECS="avc1.64001e,mp4a.40.2",AUDIO="group_aud_high"
  
  out_5.m3u8
  Signed-off-by : Steven Liu <lq@chinaffmpeg.org>
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/hlsenc.c

• Revision eec3def7c5 : Modified no memory rate control. This 2-pass rate control setting allocates bit

  16 octobre 2013, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_ratectrl.c

  
  
  Modified no memory rate control.

  This 2-pass rate control setting allocates bits based
  on first pass stats to each kf group, gf group and individual
  frame but does not correct the bits left and allocation after
  each frame.

  In other words it recommends a bit allocation for each frame
  but does not try and correct any over or under spend on a
  frame over the remainder of the clip. This reduces the accuracy
  of rate control in terms of hitting an average bitrate but prevents
  problems that may arise because early frames either use to many
  or too few bits. This mode is currently more inclined to undershoot
  than overshoot (particularly at higher data rates).

  Also minor changes to rate of adaption when recode loop is not
  enabled.

  This mode is currently enabled by default for VBR.
  It gives the following % performance gains.

  derf +0.467, +1.072
  yt 2.962, 2.645
  stdhd 1.682, 1.595,
  yt-hd 2.3, 2.174

  Change-Id : I3c84a9bf8884e5b345698ff0e19187f792c2f3a0