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• ffmpeg, dash manifest cannot be created due to unspecified pixel format

  24 septembre 2015, par artworkad シ

  I am using ffmpeg 2.8 on OSX.

  I try to convert a short mp4 video to webm for adaptive streaming like suggested here http://wiki.webmproject.org/adaptive-streaming/instructions-to-playback-adaptive-webm-using-dash like this :

  VP9_DASH_PARAMS="-tile-columns 6 -frame-parallel 1"
  
  
  
  ffmpeg -i t2.mp4 -c:v libvpx-vp9 -s 160x90 -b:v 250k -keyint_min 150 -g 150 ${VP9_DASH_PARAMS} -an -f webm -dash 1 video_160x90_250k.webm
  
  ffmpeg -i t2.mp4 -c:a libvorbis -b:a 128k -vn -f webm -dash 1 audio_128k.webm
  
  
  
  ffmpeg \
  
   -f webm_dash_manifest -i video_160x90_250k.webm \
  
   -f webm_dash_manifest -i audio_128k.webm \
  
   -c copy -map 0 -map 1 \
  
   -f webm_dash_manifest \
  
   -adaptation_sets "id=0,streams=0 id=1,streams=1" \
  
   manifest.mpd

  However this gives me a warning unspecified pixel format :

  [webm_dash_manifest @ 0x7f9414812800] Could not find codec parameters for stream 0 (Video: vp9, none, 160x90): unspecified pixel format
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  video_160x90_250k.webm: could not find codec parameters
  
  Input #0, webm_dash_manifest, from 'video_160x90_250k.webm':
  
    Metadata:
  
      encoder         : Lavf56.36.100
  
    Duration: 00:00:09.97, bitrate: 111 kb/s
  
      Stream #0:0: Video: vp9, none, 160x90, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        webm_dash_manifest_duration: 9969
  
        webm_dash_manifest_initialization_range: 437
  
        webm_dash_manifest_file_name: video_160x90_250k.webm
  
        webm_dash_manifest_track_number: 1
  
        webm_dash_manifest_cues_start: 139297
  
        webm_dash_manifest_cues_end: 139399
  
        webm_dash_manifest_bandwidth: 99164
  
        webm_dash_manifest_cluster_keyframe: 1
  
        webm_dash_manifest_cue_timestamps: 0,2085,4171,6256,8342
  
  Input #1, webm_dash_manifest, from 'audio_128k.webm':
  
    Metadata:
  
      encoder         : Lavf56.36.100
  
    Duration: 00:00:10.01, bitrate: 120 kb/s
  
      Stream #1:0: Audio: vorbis, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        webm_dash_manifest_duration: 10009
  
        webm_dash_manifest_initialization_range: 4697
  
        webm_dash_manifest_file_name: audio_128k.webm
  
        webm_dash_manifest_track_number: 1
  
        webm_dash_manifest_cues_start: 151174
  
        webm_dash_manifest_cues_end: 151240
  
        webm_dash_manifest_bandwidth: 105517
  
        webm_dash_manifest_cluster_keyframe: 1
  
        webm_dash_manifest_cue_timestamps: 0,4999,9998
  
  Output #0, webm_dash_manifest, to 'manifest.mpd':
  
    Metadata:
  
      encoder         : Lavf56.36.100
  
      Stream #0:0: Video: vp9, none, 160x90 [SAR 1:1 DAR 16:9], q=2-31, 23.98 fps, 23.98 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        webm_dash_manifest_duration: 9969
  
        webm_dash_manifest_initialization_range: 437
  
        webm_dash_manifest_file_name: video_160x90_250k.webm
  
        webm_dash_manifest_track_number: 1
  
        webm_dash_manifest_cues_start: 139297
  
        webm_dash_manifest_cues_end: 139399
  
        webm_dash_manifest_bandwidth: 99164
  
        webm_dash_manifest_cluster_keyframe: 1
  
        webm_dash_manifest_cue_timestamps: 0,2085,4171,6256,8342
  
      Stream #0:1: Video: vorbis, none, q=2-31, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        webm_dash_manifest_duration: 10009
  
        webm_dash_manifest_initialization_range: 4697
  
        webm_dash_manifest_file_name: audio_128k.webm
  
        webm_dash_manifest_track_number: 1
  
        webm_dash_manifest_cues_start: 151174
  
        webm_dash_manifest_cues_end: 151240
  
        webm_dash_manifest_bandwidth: 105517
  
        webm_dash_manifest_cluster_keyframe: 1
  
        webm_dash_manifest_cue_timestamps: 0,4999,9998
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #1:0 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
  frame=    0 fps=0.0 q=-1.0 Lsize=       1kB time=00:00:00.00 bitrate=N/A    
  
  video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  
  Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

  Nevertheless the manifest file is created. I tried to specify the pixel format :

  -pix_fmt yuv420p

  However this did not change anything. The warning remains the same.

  Any ideas why the warning appears and how to fix this ?

• How to insert frames to compensate for frames lost during capture

  5 novembre 2015, par JMor

  My original clip was 22:47 long. I captured the video in avi with Ut Video Lossless Codec at 29.97 fps, with pcm 16 bit unsigned audio.
  I am using Virtualdub with VHScrCap driver for capture.
  Virtualdub and mpc and potplayer play the captured file apparently too fast, but with the right audio pitch in the first 3-4 min, but high pitch in the rest of the video. The duration is 19:06, shorter than the original 22:47 (confirmed by mediainfo)
  The cause of the problem seems to be that I am losing more frames when capturing large HD frames.

  Regular encoding

  Encoding captured clip to mp4 :

  ffmpeg -ss 3.25 -i input.avi -map 0:0 -map 0:1 -threads 0 -c:v libx264 -profile:v main \
  
  -preset:v medium -level 3.1 -x264opts crf=26.0 -aspect 16:9 -t 1112.69 \
  
  -y -f mp4 -vf "crop=1432:808:4:46, hqdn3d=1.5:1.5:6:6, \
  
  scale=1216:684, pad=1280:720:32:18" -c:a ac3 -ac 2 -ar 48000 -b:a 160k \
  
  output.mp4

  The output is 18:32 long, framerate is still 29:97. The audio pitch is OK in the first 2 minutes, and way too high in the rest of the video.

  Trying to correct

  I try to correct it in three steps by (1) encoding a video stream that is slowed down to 23.976 fps and extracting a wav audio stream, (2) slowing speed and pitch of audio and (3) remuxing video and audio :
  (1)

  ffmpeg -ss 3.25 -i input.avi -threads 0 \
  
  -c:v libx264 -profile:v main -preset:v medium -level 3.1 -x264opts crf=26.0 \
  
  -aspect 16:9 -t 1390.862 -an -y -f mp4 -r 24000/1001 \
  
  -vf "crop=1432:808:4:46, hqdn3d=1.5:1.5:6:6, scale=1216:684, pad=1280:720:32:18, \
  
  setpts=1.25*PTS" video_out.mp4  \
  
  -t 1112.69 -y -vn -f wav  audio_out.wav

  (2) The wav audio stream is then slowed down with lower pitch with sox :

  sox --norm audio_out.mp4.wav audio_out-24.wav speed 0.8

  (3) The two streams are then remuxed with :

  ffmpeg -i video_out.mp4 -i audio_out-24.wav -map 0:0 -map 1:0 -c:v copy \
  
  -c:a ac3 -ac 2 -af aresample=resampler=soxr -ar 48000 -b:a 160k \
  
  final_output.mp4

  This time, the video duration (23:10) is closer to the original, the pitch is OK for the whole video except for the first 2-3 minutes, where it is (predictably) too low.

  I have a sense that (1) the capture log, and ffprobe give the frame by frame information that show what is the ’instantaneous’ real frame rate, and (2) that information is not used by ffmpeg encoding, but presumably could be used to correct the frame rate by inserting duplicate or interpolated frames to restitute the correct frame rate. I suspect I could get the information from (1), but have no clue how to do (2).

  If someone familiar with this type of issue could give me some advice, and point me in the right direction, I would really appreciate.

• lpc : remove unused ff_lpc_calc_levinson() function

  1er septembre 2015, par Rostislav Pehlivanov

  lpc : remove unused ff_lpc_calc_levinson() function
  Not needed anymore, it was only used by the AAC TNS
  
  encoder and was replaced with a more suitable function
  
  in the following commit.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/lpc.c
  • [DH] libavcodec/lpc.h