Typescript 将ffmpeg传输到flac编码器时出现的问题
我需要用seektables对flac文件进行编码，ffmpeg的flac编码器不包括seektables，因此我需要使用flac CLI。我试图将任意音频文件转换为可查找的flac文件，方法是首先通过ffmpeg将其传输到flac编码器Typescript 将ffmpeg传输到flac编码器时出现的问题,typescript,ffmpeg,flac,Typescript,Ffmpeg,Flac,我需要用seektables对flac文件进行编码，ffmpeg的flac编码器不包括seektables，因此我需要使用flac CLI。我试图将任意音频文件转换为可查找的flac文件，方法是首先通过ffmpeg将其传输到flac编码器 export const transcodeToFlac: AudioTranscoder<{}> = ({ source, destination }) => { return new Promise((resolve, rej
export const transcodeToFlac: AudioTranscoder<{}> = ({
source,
destination
}) => {
return new Promise((resolve, reject) => {
let totalSize = 0
const { stdout: ffmpegOutput, stderr: ffmpegError } = spawn("ffmpeg", [
"-i",
source,
"-f",
"wav",
"pipe:1"
])
const { stdout: flacOutput, stdin: flacInput, stderr: flacError } = spawn(
"flac",
["-"]
)
flacOutput.on("data", (buffer: Buffer) => {
totalSize += buffer.byteLength
})
ffmpegError.on("data", error => {
console.log(error.toString())
})
flacError.on("data", error => {
console.log(error.toString())
})
//stream.on("error", reject)
destination.on("finish", () => {
resolve({
mime: "audio/flac",
size: totalSize,
codec: "flac",
bitdepth: 16,
ext: "flac"
})
})
ffmpegOutput.pipe(flacInput)
flacOutput.pipe(destination)
})
}
-：警告，编码到标准输出时无法回写搜索点
A single INPUTFILE may be - for stdin. No INPUTFILE implies stdin. Use of
stdin implies -c (write to stdout). Normally you should use:
flac [options] -o outfilename or flac -d [options] -o outfilename
instead of:
flac [options] > outfilename or flac -d [options] > outfilename
since the former allows flac to seek backwards to write the STREAMINFO or
WAVE/AIFF header contents when necessary.
尝试使用flac--o outfilename.flac
而不仅仅是flac-
它似乎适合我，并且产生的音频长度正确（在我的情况下，这与您的情况不同）：
$rm out.flac；ffmpeg-nostdin-i~/audio/asmr/asmr\\摄像头\触摸\ \无\口音\ \无\说话-lQlZJ82ebBk.m4a-f wav-| flac--o out.flac
flac 1.3.2
Copyright (C) 2000-2009 Josh Coalson, 2011-2016 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
ffmpeg version n4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 8.2.1 (GCC) 20181127
configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
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
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/user/audio/asmr/ASMR _ Camera Touching _ No Mouthsounds _ NO TALKING-lQlZJ82ebBk.m4a':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.3.100
Duration: 00:53:29.09, start: 0.000000, bitrate: 126 kb/s
Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 -> #0:0 (aac (native) -> pcm_s16le (native))
Output #0, wav, to 'pipe:':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
ISFT : Lavf58.20.100
Stream #0:0(und): Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s (default)
Metadata:
handler_name : SoundHandler
encoder : Lavc58.35.100 pcm_s16le
-: WARNING: skipping unknown chunk 'LIST' (use --keep-foreign-metadata to keep)
13% complete, ratio=0.284size= 552816kB time=00:53:29.09 bitrate=1411.2kbits/s speed= 665x
video:0kB audio:552816kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000014%
-: WARNING: unexpected EOF; expected 1073741823 samples, got 141516800 samples
13% complete, ratio=0.283
$ ffprobe ./out.flac
ffprobe version n4.1.3 Copyright (c) 2007-2019 the FFmpeg developers
built with gcc 8.2.1 (GCC) 20181127
configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
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
Input #0, flac, from './out.flac':
Duration: 00:53:29.09, start: 0.000000, bitrate: 399 kb/s
Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
$ ffprobe ~/audio/asmr/ASMR\ _\ Camera\ Touching\ _\ No\ Mouthsounds\ _\ NO\ TALKING-lQlZJ82ebBk.m4a
ffprobe version n4.1.3 Copyright (c) 2007-2019 the FFmpeg developers
built with gcc 8.2.1 (GCC) 20181127
configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
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
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/user/audio/asmr/ASMR _ Camera Touching _ No Mouthsounds _ NO TALKING-lQlZJ82ebBk.m4a':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.3.100
Duration: 00:53:29.09, start: 0.000000, bitrate: 126 kb/s
Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
Metadata:
handler_name : SoundHandler
$ vlc out.flac
#sounds ok, even at the end
这
-：警告：跳过未知区块“列表”（使用--保留要保留的外部元数据）
无可奈何：
错误：--从stdin或到stdout编码时无法使用keep外部元数据
然而，即使我得到了
-：警告：意外EOF；预期1073741823个样本，获得141516800个样本
这就是它停止在13%（141516800*100/1073741823=13.2%）的原因，输出看起来很好，长度与输入相同
更新：
这是因为ffmpeg
没有填充输出的正确值wav
，因为它被发送到管道而不是文件，所以ffmpeg最初使用四个0xFF字节作为ChunkSize，到wav编码完成时，ffmpeg知道正确的值是什么，但它无法返回到输出管道以更新ChunkSize部分。当输出到文件时，它可以
The canonical WAVE format starts with the RIFF header:
0 4 ChunkID Contains the letters "RIFF" in ASCII form
(0x52494646 big-endian form).
4 4 ChunkSize 36 + SubChunk2Size, or more precisely:
4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
This is the size of the rest of the chunk
following this number. This is the size of the
entire file in bytes minus 8 bytes for the
two fields not included in this count:
ChunkID and ChunkSize.
8 4 Format Contains the letters "WAVE"
(0x57415645 big-endian form).
以下是输出到文件时，与输出到管道时相比，ffmpeg
wav输出的不同之处：
（注意：不要运行此操作，即使在快速处理器上，也需要几分钟的100%CPU使用率（即一个内核）
flac
不知道输入的正确大小（ChunkSize为0xffffff）
但是wav文件（输出到文件时由ffmpeg生成）将正常：
a。将wav生成文件：ffmpeg-nostdin-i~/audio/asmr/asmr\\uu\Camera\Touching\\uno\moutsounds\\uno\TALKING-lQlZJ82ebBk.m4a-f wav-toafile.wav
b。连接到flac的管道：
$ rm out2.flac; cat toafile.wav | flac - -o out2.flac
flac 1.3.2
Copyright (C) 2000-2009 Josh Coalson, 2011-2016 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
-: WARNING: skipping unknown chunk 'LIST' (use --keep-foreign-metadata to keep)
-: wrote 160381819 bytes, ratio=0.283
这是因为它正确设置了ChunkSize
值。（ChunkSize为0x21BDC046=566083654，这比输出infle.wav（其总大小为566083662字节）少8字节）问题是，从flac进行管道传输时，我仍然需要利用流。在我的代码中，目标流可能是通过管道传输到外部远程存储解决方案，如GCS。啊，我的错误，读了你的问题后，我错误地理解了你只想通过管道从ffmpeg传输到flac。问题是，正如flac-H
所说，flac无法返回到流中（因为它是一个流）来编写您所说需要的搜索点。所以我不明白你怎么能逃脱flac对管道的书写。也许尝试修改flac以写入临时文件？（可能是O_TMPFILE，这样其他人就看不到它了-我从未尝试过，但man 2 open
）然后只有在flac
进程退出后才开始将该文件传输到流。这似乎是个糟糕的解决方案，伊姆霍：（这实际上是我现在正在做的，但我讨厌它。我宁愿不使用磁盘，因为这应该是一个可伸缩的解决方案。我想我只能接受它。不过，我注意到一件奇怪的事，如果我将wav文件直接流到flac，而不使用ffmpeg，它似乎可以工作。看起来ffmpeg
无法查找back或者（因为它是一个流），因此如果将wav ffmpeg到管道而不是文件，则得到4x2=8个字节，即0xFF。4个字节是，另外4个似乎是Lavf58.2.7列表头的一部分（我不知道）但其中3个与前4个相同。可能这些信息足以让flac
不必再查找，因为现在它知道大小（块和文件）它需要计算seekpoints，因此可以正常写入而无需回寻，甚至可以写入流。我更新了答案以包含上述信息，但我猜您仍然必须从ffmpeg或flac输出到临时文件，尽管后者占用的空间似乎较少（flac vs wav），前者似乎避免了带有意外EOF
的看似危险的flac警告（注：此注释可以删除）
$ colordiff -up <(hexdump -C toafile.wav) <(hexdump -C piped.wav)
--- /dev/fd/63 2019-05-19 21:28:20.621944056 +0200
+++ /dev/fd/62 2019-05-19 21:28:20.621944056 +0200
@@ -1,8 +1,8 @@
-00000000 52 49 46 46 46 c0 bd 21 57 41 56 45 66 6d 74 20 |RIFFF..!WAVEfmt |
+00000000 52 49 46 46 ff ff ff ff 57 41 56 45 66 6d 74 20 |RIFF....WAVEfmt |
00000010 10 00 00 00 01 00 02 00 44 ac 00 00 10 b1 02 00 |........D.......|
00000020 04 00 10 00 4c 49 53 54 1a 00 00 00 49 4e 46 4f |....LIST....INFO|
00000030 49 53 46 54 0e 00 00 00 4c 61 76 66 35 38 2e 32 |ISFT....Lavf58.2|
-00000040 37 2e 31 30 33 00 64 61 74 61 00 c0 bd 21 00 00 |7.103.data...!..|
+00000040 37 2e 31 30 33 00 64 61 74 61 ff ff ff ff 00 00 |7.103.data......|
00000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00003440 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
-----------
cat piped.wav | flac - -o out2.flac
flac 1.3.2
Copyright (C) 2000-2009 Josh Coalson, 2011-2016 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
-: WARNING: skipping unknown chunk 'LIST' (use --keep-foreign-metadata to keep)
-: 13% complete, ratio=0.284-: WARNING: unexpected EOF; expected 1073741823 samples, got 141516800 samples
13% complete, ratio=0.283
$ rm out2.flac; cat toafile.wav | flac - -o out2.flac
flac 1.3.2
Copyright (C) 2000-2009 Josh Coalson, 2011-2016 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
-: WARNING: skipping unknown chunk 'LIST' (use --keep-foreign-metadata to keep)
-: wrote 160381819 bytes, ratio=0.283