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• FFmpeg concat creating corrupted video part (Media Info provided)

  6 mai 2022, par krv

  I am using concat to join a list of video files with the following command

  


  ffmpeg -f concat -safe 0 -i filesList.txt -c copy output.mp4 


  


  The issue here is that there are a few files that were recorded in slow motion on my phone. The slow-motion files have the same frame rate as the other files.

  


  But when concatenated the part where the slow-motion files are concatenated appears to be frozen / glitch (it does not play a single frame).

  


  I am able to seek forward and backward the part that does not play. So the portion of the video that contained normal files plays and as soon as the slow-motion video comes, nothing plays, and when a normal file comes it starts playing again.

  


  I am attaching the media Info of both files

  


  Info of the slow motion file :

  


  General
Complete name :     I:\concate Test\VID20210727114100.mp4
Format :    MPEG-4
Format profile :    Base Media / Version 2
Codec ID :  mp42 (isom/mp42)
File size :     27.6 MiB
Duration :  1 min 0 s
Overall bit rate :  3 825 kb/s
Encoded date :  UTC 2021-07-27 06:11:08
Tagged date :   UTC 2021-07-27 06:11:08
xyz :   +21.6146+071.2342/
com.android.version :   11

Video
ID :    1
Format :    HEVC
Format/Info :   High Efficiency Video Coding
Format profile :    Main@L3.1@Main
Codec ID :  hvc1
Codec ID/Info :     High Efficiency Video Coding
Duration :  1 min 0 s
Source duration :   1 min 0 s
Bit rate :  3 771 kb/s
Width :     1 280 pixels
Height :    720 pixels
Display aspect ratio :  16:9
Frame rate mode :   Variable
Frame rate :    30.000 FPS
Minimum frame rate :    29.910 FPS
Maximum frame rate :    30.090 FPS
Real frame rate :   240.000 FPS
Color space :   YUV
Chroma subsampling :    4:2:0
Bit depth :     8 bits
Bits/(Pixel*Frame) :    0.136
Stream size :   27.2 MiB (99%)
Source stream size :    27.2 MiB (99%)
Title :     VideoHandle
Language :  English
Encoded date :  UTC 2021-07-27 06:11:08
Tagged date :   UTC 2021-07-27 06:11:08
Color range :   Limited
Color primaries :   BT.709
Transfer characteristics :  BT.709
Matrix coefficients :   BT.709
mdhd_Duration :     60524
Codec configuration box :   hvcC


  


  Info of the regular video file

  


  
General
Complete name :     I:\concate Test\VID20210727113901.mp4
Format :    MPEG-4
Format profile :    Base Media / Version 2
Codec ID :  mp42 (isom/mp42)
File size :     39.0 MiB
Duration :  37 s 930 ms
Overall bit rate :  8 615 kb/s
Encoded date :  UTC 2021-07-27 06:09:40
Tagged date :   UTC 2021-07-27 06:09:40
xyz :   +21.6146+071.2342/
com.android.version :   11

Video
ID :    1
Format :    HEVC
Format/Info :   High Efficiency Video Coding
Format profile :    Main@L4@Main
Codec ID :  hvc1
Codec ID/Info :     High Efficiency Video Coding
Duration :  37 s 930 ms
Source duration :   37 s 900 ms
Bit rate :  8 408 kb/s
Width :     1 920 pixels
Height :    1 080 pixels
Display aspect ratio :  16:9
Frame rate mode :   Variable
Frame rate :    29.604 FPS
Minimum frame rate :    29.508 FPS
Maximum frame rate :    29.605 FPS
Real frame rate :   30.000 FPS
Color space :   YUV
Chroma subsampling :    4:2:0
Bit depth :     8 bits
Bits/(Pixel*Frame) :    0.137
Stream size :   38.0 MiB (98%)
Source stream size :    38.0 MiB (98%)
Title :     VideoHandle
Language :  English
Encoded date :  UTC 2021-07-27 06:09:40
Tagged date :   UTC 2021-07-27 06:09:40
Color range :   Limited
Color primaries :   BT.709
Transfer characteristics :  BT.709
Matrix coefficients :   BT.709
mdhd_Duration :     37930
Codec configuration box :   hvcC

Audio
ID :    2
Format :    AAC LC
Format/Info :   Advanced Audio Codec Low Complexity
Codec ID :  mp4a-40-2
Duration :  37 s 909 ms
Bit rate mode :     Constant
Bit rate :  128 kb/s
Channel(s) :    2 channels
Channel layout :    L R
Sampling rate :     48.0 kHz
Frame rate :    46.875 FPS (1024 SPF)
Compression mode :  Lossy
Stream size :   592 KiB (1%)
Title :     SoundHandle
Language :  English
Encoded date :  UTC 2021-07-27 06:09:40
Tagged date :   UTC 2021-07-27 06:09:40




  


• Why is the ffmpeg `-vsync passthrough` option not extracting the same number of frames as shown in the printed info ?

  3 juin 2022, par aininja

  I am using ffmpeg to extract all the frames in a video. To get the timestamps of each frame, I'm using the -vf showinfo filter and matching the frame numbers. The problem is that sometimes the number of frames shown in the info doesn't match up with the number of frames extracted. Why could this be happening ? Is there some default output option that I need to change to avoid this ? Is this non-deterministic behavior a bug ?

  


  The commands used to extract and inspect the frames are :

  


  $ mkdir frames
$ ffmpeg -i video.mp4 -f image2 -vf showinfo -vsync passthrough -q:v 1 frames/%05d.jpg 2> info.txt
$ NUM_FRAMES_INFO=$(cat info.txt | grep pts_time | wc -l)
$ NUM_FRAMES_JPGS=$(ls frames/*.jpg | wc -l)
$ echo ${NUM_FRAMES_INFO} ?= ${NUM_FRAMES_JPGS}


  


  For most videos, this produces the correct outputs all the time. For some videos, however, there is a mismatch occasionally. Also worth mentioning is that MP4 videos are the only ones used and tested. These videos generally only had a single video stream in them.

  


• avcodec/avs2_parser : parse more info

  13 juin 2022, par Zhao Zhili

  avcodec/avs2_parser : parse more info
  Including video resolution, framerate and picture type, etc.
  Signed-off-by : Zhao Zhili <zhilizhao@tencent.com>
  

  • [DH] libavcodec/Makefile
  • [DH] libavcodec/avs2.c
  • [DH] libavcodec/avs2.h
  • [DH] libavcodec/avs2_parser.c