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• FFmpeg re-wrap of a TS-AAC audio transport stream file to M4A-AAC : what happens by default (no "-codec copy" etc.) ?

  22 avril 2022, par esp

  What happens if you simply do ffmpeg -i aFile.ts aFile.m4a as opposed to ffmpeg -i aFile.ts -codec copy aFile.m4a, when the TS file contains only a single stream, namely AAC, and knowing that m4a files also typically contain AAC.

  


  Does ffmpeg - even in the absence of any filters etc. - decode the original AAC and re-encode back to AAC (with whatever default parameters ffmpeg assumes for that - not necessarily matching those of the original) ? Or does it do something else ?

  


  I tried this both with and without "-codec copy" and the results in each case were AAC but the files were significantly different in size (Original TS : 8.5 MB, ffmpeg'd without "-codec copy" 7 MB, ffmpeg'd with latter 5.1 MB.

  


  At https://ffmpeg.org/ffmpeg.html it is stated (under "3.2 Stream copy"...

  


  


  Stream copy is a mode selected by supplying the copy parameter to the
-codec option. It makes ffmpeg omit the decoding and encoding step for the specified stream, so it does only demuxing and muxing. It is
useful for changing the container format or modifying container-level
metadata.
Implied by the inverse of that situation is that, in the absence of "-codec copy", ffmpeg will carry out the decoding and encoding steps.

  


  


• lavc/mediacodecdec : set codec profile and level from extradata for H264+HEVC

  13 décembre 2021, par sfan5

  lavc/mediacodecdec : set codec profile and level from extradata for H264+HEVC
  This value is later passed to MediaCodec and checked at decoder init.
  
  Notably decoding of 10-bit streams before this commit would "work" without
  
  returning errors but only return garbage output (on most Android devices).
  

  • [DH] libavcodec/mediacodecdec.c

• ffmpeg says "No JPEG data found in image" when reading image paths from Linux pipe

  18 septembre 2021, par user16945608

  I'm trying to convert a set of pictures into a video, and I want to read the file paths of the pictures from the pipe. The command I would like to run looks like this :

  


  find dir/*.JPG | sort | ffmpeg -f image2pipe -r 1 -vcodec mjpeg -s 6000x4000 -pix_fmt yuvj422p -i - -vcodec libx264 -s 1080x720 -r 20 -pix_fmt yuv420p out.mkv

  


  But I keep obtaining the No JPEG data found in image error. Here is the full log :

  


  Input #0, image2pipe, from 'pipe:':
  Duration: N/A, bitrate: N/A
  Stream #0:0: Video: mjpeg, yuvj422p(bt470bg/unknown/unknown), 6000x4000, 1 fps, 1 tbr, 1 tbn, 1 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
[mjpeg @ 0x558e98cd7300] No JPEG data found in image
Error while decoding stream #0:0: Invalid data found when processing input
[swscaler @ 0x558e98ce9440] deprecated pixel format used, make sure you did set range correctly
[libx264 @ 0x558e98cdaac0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x558e98cdaac0] profile High, level 3.1, 4:2:0, 8-bit
[libx264 @ 0x558e98cdaac0] 264 - core 161 r3039 544c61f - H.264/MPEG-4 AVC codec - Copyleft
2003-2021 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=20 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, matroska, to 'out.mkv':
  Metadata:
    encoder         : Lavf58.76.100
  Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p, 1080x720, q=2-31, 20 fps, 1k tbn
    Metadata:
      encoder         : Lavc58.134.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
frame=    0 fps=0.0 q=0.0 Lsize=       1kB time=00:00:00.00 bitrate=N/A speed=   0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Conversion failed!


  


  The pictures are in the following format (with mediainfo) and the filenames are in the form DSC_1234.JPG :

  


  Format                                   : JPEG
Video
Format                                   : JPEG
Width                                    : 6 000 pixels
Height                                   : 4 000 pixels
Display aspect ratio                     : 3:2
Color space                              : YUV
Chroma subsampling                       : 4:2:2
Bit depth                                : 8 bits
Compression mode                         : Lossy


  


  Also, I would like to avoid using a solution without piping the paths (with -f image2 -i DSC_%04d.JPG for example). Do you have any idea what's happening ?