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• Converting raw video to mp4 on beaglebone with ffmpeg

  15 juin 2018, par Engineer999

  I’d really appreciate help with this one.
  I am recording video via a webcam with my beaglebone black.
  The formats supported by the camera are shown below.

      v4l2-ctl --list-formats
  
  ioctl: VIDIOC_ENUM_FMT
  
      Index       : 0
  
      Type        : Video Capture
  
      Pixel Format: 'YUYV'
  
      Name        : YUV 4:2:2 (YUYV)
  
  
  
      Index       : 1
  
      Type        : Video Capture
  
      Pixel Format: 'MJPG' (compressed)
  
      Name        : MJPEG

  When I record a raw 4:2:2 YUV video clip, there is no way to play it back to view, so I am trying to convert it to mp4 with ffmpeg.

  It states that yuyv422 is an incompatible pixel format, so I try to first convert the video to 420p with the below command, output_422.yuv being the video that I recorded from the camera.

  ffmpeg -y -pix_fmt yuyv422 -s 640x480 -r 30 -i output_422.yuv -f rawvideo -pix_fmt yuv420p -s 640x480 -r 30 output_420.yuv

  The result is :

      Input #0, rawvideo, from 'output_422.yuv':
  
    Duration: N/A, start: 0.000000, bitrate: N/A
  
      Stream #0.0: Video: rawvideo, yuyv422, 640x480, 30 tbr, 30 tbn, 30 tbc
  
  [buffer @ 0x41520] w:640 h:480 pixfmt:yuyv422
  
  [avsink @ 0x412c0] auto-inserting filter 'auto-inserted scaler 0' between the 
  
  filter 'src' and the filter 'out'
  
  [scale @ 0x44700] w:640 h:480 fmt:yuyv422 -> w:640 h:480 fmt:yuv420p 
  
  flags:0x4
  
  Output #0, rawvideo, to 'output_420.yuv':
  
    Metadata:
  
      encoder         : Lavf53.21.1
  
      Stream #0.0: Video: rawvideo, yuv420p, 640x480, q=2-31, 200 kb/s, 90k 
  
  tbn, 30 tbc
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  Error while decoding stream #0.0
  
  frame=   11 fps=  0 q=0.0 Lsize=    4950kB time=0.37 bitrate=110592.0kbits/s
  
  video:4950kB audio:0kB global headers:0kB muxing overhead 0.000000%

  I then try to convert this to mp4 like this :

  ffmpeg -f rawvideo -pix_fmt yuv420p -s 640x480 -r 30 -i output_420.yuv -vcodec libx264 output.mp4

  It looks like the conversion is successful, however when I try to play this back via vlc player, I have no video, just flickering for a few seconds. I have tried changing resolutions, frame rates etc. but no joy. Something is wrong somewhere but not sure where.

  Would anyone have some idea as to what could be wrong ? Thanks

• FFMPEG segment live video for DASH

  23 décembre 2014, par static

  I’m trying to stream live capture of desktop to my own server, which shall create an MPD with segment template for use with dash.js player.
  Using the following command i managed to get it working
  

  ffmpeg -rtbufsize 6M -f x11grab -s 1366x768 -r 10 -i :0.0 -flags +global_header \
  
  -vcodec libvpx -deadline realtime -profile:v 0 -keyint_min 1 -g 1 -cpu-used 0 \
  
  -vb 1200k -qmin 10 -qmax 42 -threads 4 -bufsize 6000k -slices 4 -map 0 -an \
  
  -f stream_segment -segment_time 2 -segment_format webm **/streams

  The output :

  Input #0, x11grab, from ':0.0': Duration: N/A, start: 1419329032.549498, bitrate: N/A
  
  Stream #0:0: Video: rawvideo (BGRA / 0x41524742), bgra, 1366x768, 10 fps, 10 tbr, 1000k tbn, 10 tbc
  
  [libvpx@ 0x23ccf60] v1.3.0 Output #0, stream_segment, ssegment, to /streams/d':
  
  Metadata:
  
  encoder : Lavf56.15.102
  
  Stream #0:0: Video: vp8 (libvpx), yuva420p, 1366x768, q=10-42, 1200 kb/s, 10 fps, 1k tbn, 10 tbc
  
  Metadata: encoder: Lavc56.13.100 libvpx
  
  Stream mapping: Stream #0:0 -> #0:0 (rawvideo (native) -> vp8 (libvpx))
  
  Press [q] to stop, [?] for help
  
  [swscaler @ 0x23ac0c0] Warning: data is not aligned! This can lead to a speedloss
  
  frame= 2839 fps= 10 q=0.0 Lsize=N/A time=00:04:43.90 bitrate=N/A
  
  video:135246kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

  If I increase the number of frames to produce better quality, the latency drastically increases and the stream is not in sync with the MPD. This is caused by the fact that keyframes are created at every frame -keyint_min 1 -g 1 because otherwise and error MEDIA_ERR_SRC_NOT_SUPPORTED is thrown by the player. This is probably because a keyframe must be found at the beginning of each segment.

  Could ffmpeg be used to generate keyframes as the first frame in each segment ? I try different values for -keyint_min x -g y, for example number of frames but with no result (probably because the number of frames stabilized after a couple a seconds, so the first 2-3 segments were produced with inconsistent number of frames, so all the keyframes were introduced in wrong positions in the segments).

• Scale2ref then join two video clips using ffmpeg

  1er janvier 2019, par A_Matar

  I have two video (with audio) clips that I want to join. The first clip has the following format :

  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 358 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
  Metadata:
  
    handler_name    : VideoHandler
  
  Stream #0:1(und): Audio: ac3 (ac-3 / 0x332D6361), 48000 Hz, stereo, fltp, 192 kb/s (default)
  
  Metadata:
  
    handler_name    : SoundHandler
  
  Side data:
  
    audio service type: main

  And the second :

  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x240, 88 kb/s, 8 fps, 8 tbr, 16384 tbn, 16 tbc (default)
  
  Metadata:
  
    handler_name    : VideoHandler
  
  Stream #0:1(und): Audio: ac3 (ac-3 / 0x332D6361), 11025 Hz, mono, fltp, 96 kb/s (default)
  
  Metadata:
  
    handler_name    : SoundHandler
  
  Side data:
  
    audio service type: main  

  I want to join the two clips ; the first followed by the latter while keeping the format options of the second clip.
  Based on reading the documentation and other questions I have reached the following command :

  ffmpeg -i secondClip.mp4 -i firstClip.mpg -filter_complex "[1:v:0][0:v:0]scale2ref=oh*mdar:ih[2nd][ref],[2nd][1:a:0][ref][0:a:0]concat=n=2:v=1:a=1[outv][outa]" -map "[outv]" -map "[outa]" output.mp4

  This gives the following errors :

  Stream mapping:
  
    Stream #0:0 (h264) -> scale2ref:ref
  
    Stream #0:1 (ac3) -> concat:in1:a0
  
    Stream #1:0 (mpeg2video) -> scale2ref:default
  
    Stream #1:1 (mp2) -> concat:in0:a0
  
    concat:out:v0 -> Stream #0:0 (libx264)
  
    concat:out:a0 -> Stream #0:1 (aac)
  
  Press [q] to stop, [?] for help
  
  [Parsed_concat_1 @ 0000017896b6f400] Input link in1:v0 parameters (size 320x240, SAR 0:1) do not match the corresponding output link in0:v0 parameters (426x240, SAR 640:639)
  
  [Parsed_concat_1 @ 0000017896b6f400] Failed to configure output pad on Parsed_concat_1
  
  Error reinitializing filters!
  
  Failed to inject frame into filter network: Invalid argument
  
  Error while processing the decoded data for stream #0:0
  
  Conversion failed!