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• ffmpeg weird x264 encoding behavior

  1er février 2016, par JMor

  I have a captured a 720x480 video with a display aspect ratio of 16:9 which I want to crop, resize and pad, but just the x264 encoding command is giving me a headache.

  (Screenshot of input.m2v) Here is my command :

  ffmpeg -ss 1861 -i input.m2v -c:v libx264 -profile:v main -preset:v medium -level 3.1 -x264opts crf=21.228 -t 60 -y -f mp4 output.mp4

  And here is the ffmpeg output :

  (Screen shot of output.mp4)

  Input #0, mpegvideo, from 'input.m2v':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: mpeg2video (Main), yuv420p(tv), 720x480 [SAR 32:27 DAR 1
  
  6:9], max. 6605 kb/s, 31.02 fps, 59.94 tbr, 1200k tbn, 59.94 tbc
  
  [libx264 @ 02ba84c0] using SAR=32/27
  
  [libx264 @ 02ba84c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 02ba84c0] profile Main, level 3.1
  
  [libx264 @ 02ba84c0] 264 - core 144 r2525 40bb568 - H.264/MPEG-4 AVC codec - Cop
  
  yleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deb
  
  lock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 m
  
  e_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chro
  
  ma_qp_offset=-2 threads=12 lookahead_threads=2 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=25 scene
  
  cut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=21.2 qcomp=0.60 qpmin
  
  =0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'output.mp4':
  
    Metadata:
  
      encoder         : Lavf56.19.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 720x48
  
  0 [SAR 32:27 DAR 16:9], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc
  
      Metadata:
  
        encoder         : Lavc56.21.102 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))

  The output size is 720x480, displayed as 853x480, as expected.
  But it looks like the frame has been vertically scaled by a factor of 1.18 and then cropped to a height of 480, so that I am losing the top and bottom of the frame. In fact, the behavior is equivalent to :

  -vf "scale=720:569,crop=720:480:0:0"

  Although I assume the aspect ratio plays a part here (I think the 1.18 factor is really (16/9)/(720/480)) I am surprised that ffmpeg would do that out of the blue. May be someone more knowledgeable than me could explain it ?

• FFMPEG blending comes out looking grayscale rather than colourful

  17 novembre 2022, par OneWorld

  When i do a blend of two pngs, it comes out looking grayscale whereas it should have colour.

  


  These are the two PNG input assets that I then create MP4s from :-

  


  

  


  

  


  Here is the command :-

  


  ffmpeg -i black_circle.png -i pikachu.png -filter_complex "[0:v]setsar=sar=1,format=rgb24[rgb1];[1:v]setsar=sar=1,format=rgb24[rgb2];[rgb1]split[out1_1][out1_2];[out1_1]crop=50:50:0:0:exact=1,setsar=1[cropped1];[cropped1][rgb2]blend=screen[blended1];[out1_2][blended1]overlay=0:0" pikachu_screened_on_circle_rgb.png


  


  And here is the output :-

  


  

  


  However, Pikachu should retain his Red, Green and Blue, but instead Pikachu looks grayscale.

  


  I was wondering why this is ?

  


  And what i need to do so that Pikachu retains his yellow skin, and rosey cheeks ?

  


  So I thought initially that it might be something to do with the white and black circle being a grayscale asset. But then I replaced the black and white circle with this asset :-

  


  

  


  and I saw that when something is black FFMPEG makes it grayscale :-

  


  

  


  The command using these two assets instead is this :-

  


  ffmpeg -i rgb_backing.png -i pikachu.png -filter_complex "[0:v]setsar=sar=1,format=rgb24[rgb1];[1:v]setsar=sar=1,format=rgb24[rgb2];[rgb1]split[out1_1][out1_2];[out1_1]crop=50:50:0:0:exact=1,setsar=1[cropped1];[cropped1][rgb2]blend=screen[blended1];[out1_2][blended1]overlay=0:0" pikachu_screened_on_rgb_backing.png


  


  Is there a way to invert black to white in FFMPEG ?

  


• Small discord bot with a set of working music commands, about 6 days ago the play function completely stopped functioning (more below)

  24 février 2021, par TheColoradoKid

  It is a small discord python bot for my server with various features, which had included music commands until they stopped out of the blue without showing any error for the problem.
It uses FFMpeg, and youtubeDl along with pytube to gather the song and store it locally to play it, I have pip updated all of these and they are definitely on the current versions as I have made sure of this online.
Any help or insight anyone could provide would be greatly appreciated. I'm sorry if the code is convoluted in the way it's written I'm still pretty new to coding and this is one of my first proper larger projects.

  


  If you need any information I'm happy to give what I can to help.

  


  Here is the code for the play command :

  


  @client.command()
async def play(ctx, *args):
    global queu
    #global autom
    if not args:
        voice = get(client.voice_clients, guild=ctx.guild)
        if not voice.is_playing():
            server = ctx.message.guild
            voice_channel = server.voice_client
            if queu:
                async with ctx.typing():
                    player = await YTDLSource.from_url(queu[0], loop=client.loop)
                    voice_channel.play(player, after=lambda e: print('Player error: %s' % e) if e else None)

                await ctx.send('**Now playing:** {}'.format(player.title))
                del(queu[0])
                # while autom == True:
                #     try:
                #         a = client.get_command('auto')
                #         await ctx.invoke(a)
                #     except:
                #         print('')
            elif not queu:
                await ctx.send("You can't play if there isn't anything in the queue\nIf auto mode was on it has now been disabled, to use it gain please add to the queue and run ``;auto on``")
                autom = False
    if args:
        global gueu
        search_keywords = ""
        print(args)
        for word in args:
            search_keywords += word
            search_keywords += '+'
        link = "https://www.youtube.com/results?search_query="
        link += search_keywords
        #print(link)
        html = urllib.request.urlopen(link)
        video_ids = re.findall(r"watch\?v=(\S{11})", html.read().decode())
        url = ("https://www.youtube.com/watch?v=" + video_ids[0])
        #print(url)
        queu.append(url)
        #print(queu)
        await ctx.send("``{}`` added to queue!\n If the song doesn't start please either let the current song end and run ``;play``/``;next`` again or run ``;next`` to play now".format(url))
        try:
            p = client.get_command('play')
            await ctx.invoke(p)
        except:
            print('failed')