使用 GCP Transcoder API 进行转码会导致时间间隔

编程问答 2022-05-23

问题描述

我一直在尝试 GCP 的 Transcoder API，但在某些情况下随机变得比指定的时间短。

具体情况如下：

  1. 指定startTimeOffset和endTimeOffset（截断视频前后2秒）
  2. fMP4 用作容器
  3. 输入视频为 mp4，在 iPad Pro 上进行屏幕录制

比如我不指定startTimeOffset和endTimeOffset，时间不会缩短。此外，当为容器指定 MPEG2-TS 时也没有问题。视频本身可能有问题，但我还没有找到如何设置的线索。

我不确定这是转码器 API 的问题还是我的问题。

测试输入视频：https://gofile.io/d/DUT9rr

❯ ffprobe input.mp4
ffprobe version 4.3.1 Copyright (c) 2007-2020 the FFmpeg developers
  built with Apple clang version 12.0.0 (clang-1200.0.32.28)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_8 --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-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --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 --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0,mov,mp4,m4a,3gp,3g2,mj2,from 'input.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: isommp41mp42
    creation_time   : 2021-02-26T15:08:58.000000Z
  Duration: 00:02:51.15,start: 0.000000,bitrate: 551 kb/s
    Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D),44100 Hz,stereo,fltp,246 kb/s (default)
    Metadata:
      creation_time   : 2021-02-26T15:08:58.000000Z
      handler_name    : Core Media Audio
    Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661),yuvj420p(pc,bt709/bt709/iec61966-2-1),1920x1342,302 kb/s,12.39 fps,120 tbr,600 tbn,1200 tbc (default)
    Metadata:
      rotate          : 180
      creation_time   : 2021-02-26T15:08:58.000000Z
      handler_name    : Core Media Video
    Side data:
      displaymatrix: rotation of -180.00 degrees

#!/bin/bash -eu

cat > request.json << EOF
{
  "config": {
    "inputs": [
      {
        key: "input0"
      }
    ],"editList": [
      {
        "key": "atom0","inputs": [
          "input0"
        ],"startTimeOffset": "2s","endTimeOffset": "169s",},],"elementaryStreams": [
      {
        "videoStream": {
          "codec": "h265","heightPixels": 480,"bitrateBps": 1200000,"rateControlMode": "vbr","enableTwoPass": true,"frameRate": 30,"crfLevel": 31,"gopDuration": "3.0s","key": "h265-stream0"
      },{
        "videoStream": {
          "codec": "h265","heightPixels": 720,"bitrateBps": 1550000,"key": "h265-stream1"
      },"heightPixels": 1080,"bitrateBps": 2600000,"key": "h265-stream2"
      },{
        "audioStream": {
          "codec": "aac","bitrateBps": 64000,"channelCount": 2,"channelLayout": [
            "fl","fr"
          ],"sampleRateHertz": 48000
        },"key": "audio-stream0"
      },"muxStreams": [
      {
        "key": "media-sd","fileName": "media-sd.m4s","container": "fmp4","elementaryStreams": [
          "h265-stream0","segmentSettings": {
          "individualSegments": true
        },{
        "key": "media-hd","fileName": "media-hd.m4s","elementaryStreams": [
          "h265-stream1",{
        "key": "media-fhd","fileName": "media-fhd.m4s","elementaryStreams": [
          "h265-stream2",{
        "key": "audio-only","fileName": "audio-only.m4s","elementaryStreams": [
          "audio-stream0"
        ],"manifests": [
      {
        "fileName": "manifest-h265.mpd","type": "DASH","muxStreams": [
          "media-sd","media-hd","media-fhd","audio-only",]
      },]
  }
}
EOF

curl -X POST \
-H "Authorization: Bearer "$(gcloud auth application-default print-access-token) \
-H "Content-Type: application/json; charset=utf-8" \
-d @request.json \
https://transcoder.googleapis.com/v1beta1/projects/MY_PROJECT/locations/asia-east1/jobTemplates?jobTemplateId=test-template

#!/bin/bash -eu

cat > request.json << EOF
{
  "inputUri": "gs://my-bucket/input.mp4","outputUri": "gs://my-bucket/output/","templateId": "test-template"
}
EOF

curl -X POST \
-H "Authorization: Bearer "$(gcloud auth application-default print-access-token) \
-H "Content-Type: application/json; charset=utf-8" \
-d @request.json \
https://transcoder.googleapis.com/v1beta1/projects/MY_PROJECT/locations/asia-east1/jobs

以下是生成的清单文件的 ffprobe，比指定的时间短 2 秒。 （预期：00:02:47.00，实际：00:02:45.00）在这种情况下，这是一个 2 秒的间隔，但可以是 10 秒或 30 秒，并且因视频而异。

❯ ffprobe manifest-h265.mpd
ffprobe version 4.3.1 Copyright (c) 2007-2020 the FFmpeg developers
  built with Apple clang version 12.0.0 (clang-1200.0.32.28)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_8 --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-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --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 --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0,dash,from 'manifest-h265.mpd':
  Duration: 00:02:45.00,bitrate: 0 kb/s
  Program 0
    Stream #0:0: Video: hevc (Main) (hvc1 / 0x31637668),yuv420p(tv,bt709/unknown/unknown),686x480,112 kb/s,30 fps,10k tbn,30 tbc
    Metadata:
      variant_bitrate : 113679
      id              : 113679
    Stream #0:1: Video: hevc (Main) (hvc1 / 0x31637668),1030x720,205 kb/s,30 tbc
    Metadata:
      variant_bitrate : 189219
      id              : 189219
    Stream #0:2: Video: hevc (Main) (hvc1 / 0x31637668),1544x1080,384 kb/s,30 tbc
    Metadata:
      variant_bitrate : 358043
      id              : 358043
    Stream #0:3: Audio: aac (LC) (mp4a / 0x6134706D),48000 Hz,65 kb/s
    Metadata:
      variant_bitrate : 70245
      id              : 70245

以下是 h264 + MPEG2-TS + Apple HLS 指定的时间。

❯ ffprobe manifest-h264.m3u8 | pbcopy
ffprobe version 4.3.1 Copyright (c) 2007-2020 the FFmpeg developers
  built with Apple clang version 12.0.0 (clang-1200.0.32.28)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_8 --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-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --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 --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
[hls @ 0x7fe23100f200] Opening 'h264-sd-ts.m3u8' for reading
[hls @ 0x7fe23100f200] Skip ('#EXT-X-VERSION:4')
[hls @ 0x7fe23100f200] Opening 'h264-hd-ts.m3u8' for reading
[hls @ 0x7fe23100f200] Skip ('#EXT-X-VERSION:4')
[hls @ 0x7fe23100f200] Opening 'h264-fhd-ts.m3u8' for reading
[hls @ 0x7fe23100f200] Skip ('#EXT-X-VERSION:4')
[hls @ 0x7fe23100f200] Opening 'h264-sd0000000000.ts' for reading
[hls @ 0x7fe23100f200] Opening 'h264-hd0000000000.ts' for reading
[hls @ 0x7fe23100f200] Opening 'h264-fhd0000000000.ts' for reading
Input #0,hls,from 'manifest-h264.m3u8':
  Duration: 00:02:47.00,bitrate: 0 kb/s
  Program 0
    Metadata:
      variant_bitrate : 511576
    Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B),yuv420p,90k tbn,2000k tbc
    Metadata:
      variant_bitrate : 511576
    Stream #0:1: Audio: aac (LC) ([15][0][0][0] / 0x000F),fltp
    Metadata:
      variant_bitrate : 511576
  Program 1
    Metadata:
      variant_bitrate : 793711
    Stream #0:2: Video: h264 (High) ([27][0][0][0] / 0x001B),2000k tbc
    Metadata:
      variant_bitrate : 793711
    Stream #0:3: Audio: aac (LC) ([15][0][0][0] / 0x000F),fltp
    Metadata:
      variant_bitrate : 793711
  Program 2
    Metadata:
      variant_bitrate : 1305288
    Stream #0:4: Video: h264 (High) ([27][0][0][0] / 0x001B),2000k tbc
    Metadata:
      variant_bitrate : 1305288
    Stream #0:5: Audio: aac (LC) ([15][0][0][0] / 0x000F),fltp
    Metadata:
      variant_bitrate : 1305288

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

如果你已经找到好的解决方法，欢迎将解决方案带上本链接一起发送给小编。

小编邮箱:dio#foxmail.com (将#修改为@）

ffmpegfmp4google-cloud-platformmpeg-dashvideo

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