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• avcodec/sanm : support "StarWars - Making Magic" video

  1er mai, par Manuel Lauss

  avcodec/sanm : support "StarWars - Making Magic" video
  Videos of "StarWars - Making Magic" consist of 640x480 codec3 frames
  
  which establish a background, and a 320x240 codec48 video put on top
  
  at random left/top offsets.
  To support this, a new default buffer "fbuf", which holds the final
  
  image to be presented, is added, since codec37/47/48 need their 2/3 buffers
  
  to be private to themselves.  The decoded result is then copied to the fbuf,
  
  honoring the left/top offsets if required.
  Signed-off-by : Manuel Lauss <manuel.lauss@gmail.com>
  

  • [DH] libavcodec/sanm.c

• avcodec/mpegvideoencdsp : speed up draw_edges_8_c by inlining it for all used edge...

  21 août 2024, par Ramiro Polla

  avcodec/mpegvideoencdsp : speed up draw_edges_8_c by inlining it for all used edge widths
  This commit also restricts w to 4, 8, or 16.
  Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz :
  
                                      before    after
  
  draw_edges_8_1724_4_c :             46796.5   7141.7  ( 6.55x)
  
  draw_edges_8_1724_8_c :             43584.5   7216.5  ( 6.04x)
  
  draw_edges_8_1724_16_c :            47007.2  10080.5  ( 4.66x)
  
  draw_edges_128_407_4_c :            11199.0   4185.0  ( 2.68x)
  
  draw_edges_128_407_8_c :            10660.2   4418.0  ( 2.41x)
  
  draw_edges_128_407_16_c :           11800.2   4634.5  ( 2.55x)
  
  draw_edges_1080_31_4_c :             1356.5    634.7  ( 2.14x)
  
  draw_edges_1080_31_8_c :             1972.0   1430.2  ( 1.38x)
  
  draw_edges_1080_31_16_c :            4621.0   4009.7  ( 1.15x)
  
  draw_edges_1920_4_4_c :               834.5    795.2  ( 1.05x)
  
  draw_edges_1920_4_4_negstride_c :     821.7    802.0  ( 1.02x)
  
  draw_edges_1920_4_8_c :              2782.2   2650.7  ( 1.05x)
  
  draw_edges_1920_4_8_negstride_c :    2724.7   2670.0  ( 1.02x)
  
  draw_edges_1920_4_16_c :             6437.5   6327.7  ( 1.02x)
  
  draw_edges_1920_4_16_negstride_c :   6395.2   6349.5  ( 1.01x)
  A55 :
  
                                      before    after
  
  draw_edges_8_1724_4_c :             52540.4  19739.2  ( 2.66x)
  
  draw_edges_8_1724_8_c :             45386.9  19847.4  ( 2.29x)
  
  draw_edges_8_1724_16_c :            51995.4  23284.7  ( 2.23x)
  
  draw_edges_128_407_4_c :            13401.1   6988.2  ( 1.92x)
  
  draw_edges_128_407_8_c :            12218.4   7527.9  ( 1.62x)
  
  draw_edges_128_407_16_c :           13695.9   8207.2  ( 1.67x)
  
  draw_edges_1080_31_4_c :             3702.9   3110.4  ( 1.19x)
  
  draw_edges_1080_31_8_c :             6015.6   5643.2  ( 1.07x)
  
  draw_edges_1080_31_16_c :           12281.9  11901.4  ( 1.03x)
  
  draw_edges_1920_4_4_c :              3957.9   3970.2  ( 1.00x)
  
  draw_edges_1920_4_4_negstride_c :    3964.1   3825.2  ( 1.04x)
  
  draw_edges_1920_4_8_c :              7757.9   7676.4  ( 1.01x)
  
  draw_edges_1920_4_8_negstride_c :    7923.6   7812.4  ( 1.01x)
  
  draw_edges_1920_4_16_c :            14791.6  15143.9  ( 0.98x)
  
  draw_edges_1920_4_16_negstride_c :  14788.6  15163.4  ( 0.98x)
  A76 :
  
                                      before   after
  
  draw_edges_8_1724_4_c :             39786.0  4968.5  ( 8.01x)
  
  draw_edges_8_1724_8_c :             32971.5  5069.5  ( 6.50x)
  
  draw_edges_8_1724_16_c :            40056.0  6017.2  ( 6.66x)
  
  draw_edges_128_407_4_c :             9517.2  1210.5  ( 7.86x)
  
  draw_edges_128_407_8_c :             8035.7  1346.2  ( 5.97x)
  
  draw_edges_128_407_16_c :            9946.5  1648.2  ( 6.03x)
  
  draw_edges_1080_31_4_c :             1308.0   660.7  ( 1.98x)
  
  draw_edges_1080_31_8_c :             1785.5  1270.7  ( 1.41x)
  
  draw_edges_1080_31_16_c :            3266.7  2591.5  ( 1.26x)
  
  draw_edges_1920_4_4_c :              1151.0  1090.7  ( 1.06x)
  
  draw_edges_1920_4_4_negstride_c :    1153.7  1096.5  ( 1.05x)
  
  draw_edges_1920_4_8_c :              2220.7  2186.5  ( 1.02x)
  
  draw_edges_1920_4_8_negstride_c :    2218.5  2193.5  ( 1.01x)
  
  draw_edges_1920_4_16_c :             4324.2  4230.0  ( 1.02x)
  
  draw_edges_1920_4_16_negstride_c :   4310.7  4233.0  ( 1.02x)
  

  • [DH] libavcodec/mpegvideoencdsp.c

• Frame duration issues when trimming videos in MATLAB/ffmpeg ?

  18 septembre 2024, par twilightecologist

  I have two videos (A.MOV and B.MOV), that are supposed to be perfectly synced. However, Video A (3708 frames), has 5 more frames than Video B (3703 frames). When I look at the timestamps of these frames, the extra A frames are at the very end of the video. In addition, the last frame in each video is a "padded" frame, with a duration much longer (around 10 times) than that of the other frames.

  


  I need my videos to be perfectly synced, with the same frame number. Since the extra frames are at the end of the video, I want to trim off the extra frames in A, as well as trim the "padded" long frame off of each video.

  


  I currently am running the below MATLAB code to do so,

  


  % Specify the input and output file names
inputVideoFile = 'A.MOV';
intermediateVideoFile = 'A_trim_temp.mp4'; % Temporary file
finalOutputFile = 'A_trim_mat.mp4'; % Final output file
% Create VideoReader object
videoReader = VideoReader(inputVideoFile);
% Get the total number of frames and other properties
numFrames = videoReader.NumFrames;
frameRate = videoReader.FrameRate;
videoHeight = videoReader.Height;
videoWidth = videoReader.Width;
% Create VideoWriter object
videoWriter = VideoWriter(intermediateVideoFile, 'MPEG-4');
videoWriter.FrameRate = frameRate;
open(videoWriter);
% Read and write frames except the last 5
for i = 1:(numFrames - 5)
    frame = read(videoReader, i);
    writeVideo(videoWriter, frame);
end
% Close the VideoWriter object
close(videoWriter);
% Handle audio extraction and trimming
% This requires an external tool like FFmpeg, as MATLAB does not handle audio directly
% Command to extract audio
audioExtractCommand = sprintf('ffmpeg -i "%s" -q:a 0 -map a audio_original.wav', inputVideoFile);
[status, cmdout] = system(audioExtractCommand);
if status ~= 0
    error('Error extracting audio: %s', cmdout);
end
% Command to trim audio (matching the length of the trimmed video)
audioTrimCommand = sprintf('ffmpeg -i audio_original.wav -ss 0 -t %f -c copy audio_trimmed.wav', (numFrames - 5) / frameRate);
[status, cmdout] = system(audioTrimCommand);
if status ~= 0
    error('Error trimming audio: %s', cmdout);
end
% Command to merge trimmed audio with the video
audioMergeCommand = sprintf('ffmpeg -i "%s" -i audio_trimmed.wav -c:v copy -c:a aac -strict experimental "%s"', intermediateVideoFile, finalOutputFile);
[status, cmdout] = system(audioMergeCommand);
if status ~= 0
    error('Error merging audio and video: %s', cmdout);
end
% Clean up temporary audio files
delete('audio_original.wav');
delete('audio_trimmed.wav');
delete(intermediateVideoFile); % Delete the intermediate file


  


  When I run the above code for Video B, I change

  


  for i = 1:(numFrames - 5)


  


  to

  


  for i = 1:(numFrames - 1)


  


  to remove the padded last frame.

  


  When I run this for both videos, they both return the same frame number (yay !). The timestamps of every frame between A_trim_mat and B_trim_mat match, except for the timestamp of the last frame ( A_trim_mat = 30.8910, B_trim_mat = 30.8890), and perhaps most concerningly, the frame duration between the last two frames of each video is negative (A_trim_mat = -0.0063, B_trim_mat = -0.0083). The duration for all other frames is constant at 0.0083 for both videos.

  


  Any suggestions for how to remedy this are much appreciated. Ideally, I want the timestamps for every frame to match between A and B, and I want the frame duration for each frame to match between A and B.