c - 添加 avfilter 后编译 FFMPEG/libav 代码时出错

Question

我的编码和解码使用 ffmpeg 和 libav 工作正常，但后来我在编码步骤中添加了一个过滤器来旋转我的视频，它不再在我的 docker 机器上工作，但它在本地工作。

在 docker 中编译时的错误信息是

//usr/local/lib/libavfilter.a(vf_pp.o): In function `pp_init':
/var/tmp/ffmpeg/libavfilter/vf_pp.c:56: undefined reference to `pp_get_mode_by_name_and_quality'
//usr/local/lib/libavfilter.a(vf_pp.o): In function `pp_uninit':
/var/tmp/ffmpeg/libavfilter/vf_pp.c:161: undefined reference to `pp_free_mode'
/var/tmp/ffmpeg/libavfilter/vf_pp.c:163: undefined reference to `pp_free_context'
//usr/local/lib/libavfilter.a(vf_pp.o): In function `pp_filter_frame':
/var/tmp/ffmpeg/libavfilter/vf_pp.c:142: undefined reference to `pp_postprocess'
//usr/local/lib/libavfilter.a(vf_pp.o): In function `pp_config_props':
/var/tmp/ffmpeg/libavfilter/vf_pp.c:115: undefined reference to `pp_get_context'
collect2: error: ld returned 1 exit status

这些是我在 docker 文件中的相关配置

# Install libx264 for video encoding.
RUN cd /var/tmp && curl -L http://ftp.videolan.org/pub/videolan/x264/snapshots/x264-snapshot-20190103-2245-stable.tar.bz2 > x264.tar.bz2 && \
    echo "21cb6e2bb660f863713fb9f752654c65191e032dac1329ec113786c69f0f75c1  x264.tar.bz2" > x264.sha256sum && \
    shasum -a 256 -c x264.sha256sum && \
    tar xjf x264.tar.bz2 && \
    cd x264-snapshot-20190103-2245-stable && \
    ./configure \
        --enable-static \
        --enable-pic \
        --disable-cli \
        --disable-avs \
        --disable-opencl && \
    make -j8 && \
    make install-lib-static

# Compile ffmpeg.
COPY ffmpeg.tar /var/tmp/ffmpeg.tar
RUN cd /var/tmp && tar xf ffmpeg.tar && \
    cd ffmpeg && \
    ./configure \
        --cc=/usr/bin/clang-6.0 \
        --cxx=/usr/bin/clang++-6.0 \
        --extra-libs="-lpthread" \
        --enable-gpl \
        # without pic - opencv will throw up errors
        --enable-pic \
        --enable-libx264 \
        --disable-network && \
     make -j 8 && \
     make install

不确定这是否相关，但这是我的标志

LDFLAGS: -lavcodec -lavfilter -lswscale -lavutil -lswresample -lx264 -lm -lz

这是我本地的 ffmpeg 配置和版本

ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.2_2 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100

这是我的 docker 机器的输出

ffmpeg version 4.1.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with clang version 6.0.0-1~bpo9+1 (tags/RELEASE_600/final)
  configuration: --cc=/usr/bin/clang-6.0 --cxx=/usr/bin/clang++-6.0 --extra-libs=-lpthread --enable-gpl --enable-pic --enable-libx264 --disable-network
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100

如何修复我的配置，使其像在本地一样工作？我没有专门配置我的本地环境，所以它将使用默认配置。

Answer 1

你不见了-lpostproc在您的 LDFLAGS .此外，顺序应该是正确的:

LDFLAGS=-lavfilter -lswscale -lpostproc -lswresample -lavcodec -lavutil -lx264 -lm -lz