Question

我使用ffmpeg将PCM数据编码为AAC格式：以下是我设置上下文对象的代码：

-(id)encode:(short*)data{
    AVCodecContext  *audioCodec;
    AVCodec *codec;

    avcodec_register_all();

    //Set up audio encoder
    codec = avcodec_find_encoder(AV_CODEC_ID_AAC);
    if (codec == NULL){
        NSLog(@"no codec");
     }
    audioCodec = avcodec_alloc_context3(codec);
    audioCodec->strict_std_compliance = -2;
    audioCodec->bit_rate = 64000;
    audioCodec->sample_fmt = AV_SAMPLE_FMT_S16;
    audioCodec->sample_rate = 8000;
    audioCodec->channels = 2;
    audioCodec->profile = FF_PROFILE_AAC_MAIN;
    audioCodec->time_base = (AVRational){1, 8000};
    audioCodec->codec_type = 1;
    if (avcodec_open2(audioCodec, codec, NULL)) {
        NSLog(@"could not open codec");

    }
     return @"NO";
}

我总是得到一个错误日志： aac @ 0x151cda00]指定的样本格式s16无效或不受支持

如果我没有提供任何样本格式，我会得到相同的日志： aac @ 0x151cda00]指定的样本格式-1无效或不受支持

以及avcodec_open2()给出日志的原因无法打开编解码器;

一些人可以告诉我这是什么问题吗？

ffmpeg编译脚本如下：

#!/bin/sh

# directories
SOURCE="ffmpeg"
FAT="fat"
VERSION="2.0.2"

SCRATCH="scratch"
# must be an absolute path
THIN=`pwd`/"thin"

# absolute path to x264 library
#X264=`pwd`/fat_x264

CONFIGURE_FLAGS="--enable-cross-compile \
    --disable-network \
    --disable-encoders  \
    --disable-decoders \
    --disable-muxers \
    --disable-demuxers \
    --disable-protocols \
    --disable-devices \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-ffserver \
    --disable-avdevice \
    --disable-avfilter \
    --disable-iconv \
    --disable-bzlib \
    --disable-mmx \
    --disable-mmxext \
    --disable-amd3dnow \
    --disable-amd3dnowext \
    --disable-sse \
    --disable-sse2 \
    --disable-sse3 \
    --disable-sse4 \
    --disable-avx \
    --disable-fma4 \
    --disable-swresample \
    --disable-postproc \
    --disable-bsfs \
    --disable-filters \
    --disable-asm \
    --disable-yasm \
    --disable-debug \
    --disable-doc \
    --disable-armv5te \
    --disable-armv6 \
    --disable-armv6t2 \
    --enable-protocol=file \
    --enable-avformat \
    --enable-avcodec \
    --enable-swscale \
    --enable-demuxer=mp3 \
    --enable-demuxer=aac \
    --enable-demuxer=image2 \
    --enable-demuxer=mov \
    --enable-decoder=rawvideo \
    --enable-demuxer=h263 \
    --enable-demuxer=h264 \
    --enable-decoder=mp3 \
    --enable-decoder=aac \
    --enable-decoder=mjpeg \
    --enable-decoder=h263 \
    --enable-decoder=h264 \
    --enable-decoder=mpeg4 \
    --enable-encoder=mp3 \
    --enable-encoder=aac \
    --enable-encoder=mjpeg \
    --enable-encoder=h263 \
    --enable-encoder=h264 \
    --enable-encoder=mpeg4 \
    --enable-parser=mp3 \
    --enable-parser=aac \
    --enable-parser=h264 \
    --enable-pic"

if [ "$X264" ]
then
    CONFIGURE_FLAGS="$CONFIGURE_FLAGS --enable-gpl --enable-libx264"
fi

# avresample
#CONFIGURE_FLAGS="$CONFIGURE_FLAGS --enable-avresample"

ARCHS="arm64 armv7s armv7 x86_64 i386"

COMPILE="y"
LIPO="y"

DEPLOYMENT_TARGET="6.0"

if [ "$*" ]
then
    if [ "$*" = "lipo" ]
    then
        # skip compile
        COMPILE=
    else
        ARCHS="$*"
        if [ $# -eq 1 ]
        then
            # skip lipo
            LIPO=
        fi
    fi
fi

if [ "$COMPILE" ]
then
    CWD=`pwd`
    for ARCH in $ARCHS
    do
        echo "building $ARCH..."
        mkdir -p "$SCRATCH/$ARCH"
        cd "$SCRATCH/$ARCH"

        CFLAGS="-arch $ARCH"
        if [ "$ARCH" = "i386" -o "$ARCH" = "x86_64" ]
        then
            PLATFORM="iPhoneSimulator"
            CFLAGS="$CFLAGS -mios-simulator-version-min=$DEPLOYMENT_TARGET"
        else
            PLATFORM="iPhoneOS"
            CFLAGS="$CFLAGS -mios-version-min=$DEPLOYMENT_TARGET"
            if [ "$ARCH" = "arm64" ]
            then
                EXPORT="GASPP_FIX_XCODE5=1"
            fi
        fi

        XCRUN_SDK=`echo $PLATFORM | tr '[:upper:]' '[:lower:]'`
        CC="xcrun -sdk $XCRUN_SDK clang"
        CXXFLAGS="$CFLAGS"
        LDFLAGS="$CFLAGS"
        if [ "$X264" ]
        then
            CFLAGS="$CFLAGS -I$X264/include"
            LDFLAGS="$LDFLAGS -L$X264/lib"
        fi

        $CWD/$SOURCE/configure \
            --target-os=darwin \
            --arch=$ARCH \
            --cc="$CC" \
            $CONFIGURE_FLAGS \
            --extra-cflags="$CFLAGS" \
            --extra-cxxflags="$CXXFLAGS" \
            --extra-ldflags="$LDFLAGS" \
            --prefix="$THIN/$ARCH"

        make -j3 install $EXPORT
        cd $CWD
    done
fi

if [ "$LIPO" ]
then
    echo "building fat binaries..."
    mkdir -p $FAT/lib
    set - $ARCHS
    CWD=`pwd`
    cd $THIN/$1/lib
    for LIB in *.a
    do
        cd $CWD
        lipo -create `find $THIN -name $LIB` -output $FAT/lib/$LIB
    done

    cd $CWD
    cp -rf $THIN/$1/include $FAT
fi

Answer 1

我遇到了类似的问题，因为我不知道我的Windows Phone支持哪种格式。（原来是AV_SAMPLE_FMT_FLTP）

我最终查看了avcodec_open2源代码（https://www.ffmpeg.org/doxygen/2.1/libavcodec_2utils_8c_source.html）

并发现它正在引用编解码器以查看支持哪些样本。

考虑到这一点，你可以这样做： audioCodec-＆gt; sample_fmt = audioCodec-＆gt; codec-＆gt; sample_fmts [0];

Answer 2

错误可能会产生误导。

尝试删除该行： audioCodec->profile = FF_PROFILE_AAC_MAIN或将其更改为audioCodec->profile = FF_PROFILE_UNKNOWN
尝试在fdk-aac编码器中进行编译：https://github.com/mstorsjo/fdk-aac输出质量要好得多，它支持各种采样率和比特率。据我所知，原生ffmpeg编码器相比并不是很好。但也许你不能使用fdk-aac因为许可证（你需要向Fraunhofer支付专利使用费）：

http://www.vialicensing.com/licensing/aac-faq.aspx

http://www.vialicensing.com/licensing/aac-fees.aspx

指定的样本格式s16无效或不受支持

2 个答案: