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• Does there exist fonts that supprot all languages in the FFmpeg ?

  20 novembre 2024, par phil lx

  I encountered an issue while using FFmpeg to composite a video. After analyzing the user's request, I discovered that the subtitles included Korean text, which caused the process to hang. To address this, I downloaded a Korean font and placed it in the server's fonts directory. This resolved the problem temporarily.

  


  However, this solution is not comprehensive. Another user later requested a video that included traditional Chinese characters, which caused the process to hang again.

  


  成吉思汗，传统蒙古文写作ᠴᠢᠩᠭᠢᠰ ᠬᠠᠭᠠᠨ，拉丁蒙古文写作Činggis Qaγan，西里尔蒙古文写作Чингис Хаан，他是蒙古族乞颜部人

  


  I would like to know if there is a universal font style that supports all languages to prevent such issues in the future.

  


  For reference, I currently use the Alibaba PuHuiTi font, which I downloaded from this link : https://www.zitijia.com/downloadpage?itemid=250417369808129081.

  


  Here is the relevant portion of my code :

  


  filters1 = []
    filters1.append(f"[0:v]crop={int(0.8*width)}:{int(0.8*height)}:{int(0.1*width)}:0,scale={width}:{height}[vout]")
    if add_sub == 1:
        filters1.append(f"[vout]subtitles={srt_path}:force_style='Fontname=Alibaba PuHuiTi,Fontsize={font_size},PrimaryColour={font_color},OutlineColour={font_border_color},MarginV={font_position*(288-font_size)}'[vout]")

    filter_complex1 = ';'.join(filters1)

    command = [
        'ffmpeg',
        '-y',  # 覆盖输出文件
        '-threads', '12',
        # '-loglevel', 'error',
        
        # 第一个输入
        '-f', 'rawvideo',  # 输入为原始视频数据
        '-vcodec', 'rawvideo',
        '-s', f'{width}x{height}',  # 图像尺寸
        '-pix_fmt', 'rgb24',  # 输入像素格式
        '-r', '30',  # 帧率
        '-i', '-',  # 输入从stdin

        # 复杂过滤器
        '-filter_complex', filter_complex1,

        # 映射输出流
        '-map', '[vout]',  # 使用裁剪后的视频
        # '-map', '[audio_out]',  # 使用混合后的音频

        # 输出选项
        '-vcodec', 'h264_nvenc',  # 输出视频编码
        '-pix_fmt', 'yuv420p',  # 输出像素格式
        # '-acodec', 'aac',  # 输出音频编码
        '-strict', 'experimental',  # 兼容性模式

        # 输出文件
        video_withoutspeed_path
    ]


  


  As shown above. hey-hey-hey

  


• avcodec/speexdec : Consider mode in frame size check

  26 décembre 2021, par Michael Niedermayer

  avcodec/speexdec : Consider mode in frame size check
  No speex samples with non default frame sizes are known (to me)
  
  the official speexenc seems to only generate the 3 default ones.
  
  Thus it may be that the fuzzer samples where the first non default
  
  values encountered by the decoder.
  
  Possibly the "<" should be " !="
  Fixes : out of array access
  
  Fixes : 42821/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SPEEX_fuzzer-5640695772217344
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/speexdec.c

• three ways to achieve an H264 file

  18 mars 2016, par Kindermann

  here I have three ways to get an H264 file, like all forensic scientists, I am very curious about the differences between them :

  1.

  ffmpeg -i video.mp4 video.h264

  2.

  ffmpeg -i video.mp4 -vcodec copy -an -f h264 video.h264

  3. Using the example "demuxing_decoding.c" provided on the ffmpeg official website :
  http://ffmpeg.org/doxygen/trunk/demuxing_decoding_8c-example.html

  Obviously, the first one does the transformation, and the second one does the demuxing. They render different H264 files which however have similar file sizes(in my case, it’s about say 24 MB). Suprisingly, the third one, which is also supposed to do the demuxing job, renders an H264 file with 8.4 GB ! Why ?

  What I wondered is really, how the interiors of these three methods work ?(The third one is already in source code, therefore it’s quite easy to have an insight) What about the first two commands ? What APIs are called when executing these two commands and how those APIs are called(namely, in what kind of sequences they are called) and things like that.
  One thing that is also important to me is, i have no idea how I can trace the execution routines of ffmpeg command lines. I want to see what’s going on behind ffmpeg commands in source code version. Is it possible ?

  I appreciate any comment.