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MediaConvert introduces audio-video sync issue

0

Hi. I'm having an issue with MediaConvert. Running a fairly simple job on what seems like a rather unremarkable H.264 MP4 is resulting in sync issues between audio and video in the output. The sync starts out okay, but by the end of the output video it is noticeably off.

Here's the MediaInfo output for the input MP4:

General  
Count                                    : 331  
Count of stream of this kind             : 1  
Kind of stream                           : General  
Kind of stream                           : General  
Stream identifier                        : 0  
Count of video streams                   : 1  
Count of audio streams                   : 1  
Video_Format_List                        : AVC  
Video_Format_WithHint_List               : AVC  
Codecs Video                             : AVC  
Audio_Format_List                        : AAC LC  
Audio_Format_WithHint_List               : AAC LC  
Audio codecs                             : AAC LC  
Complete name                            : 59397af7-aba0-4b8f-ac14-4c351ec69688.mp4  
File name extension                      : 59397af7-aba0-4b8f-ac14-4c351ec69688.mp4  
File name                                : 59397af7-aba0-4b8f-ac14-4c351ec69688  
File extension                           : mp4  
Format                                   : MPEG-4  
Format                                   : MPEG-4  
Format/Extensions usually used           : braw mov mp4 m4v m4a m4b m4p m4r 3ga 3gpa 3gpp 3gp 3gpp2 3g2 k3g jpm jpx mqv ismv isma ismt f4a f4b f4v  
Commercial name                          : MPEG-4  
Format profile                           : Base Media  
Internet media type                      : video/mp4  
Codec ID                                 : isom  
Codec ID                                 : isom (isom/iso2/avc1/mp41)  
Codec ID/Url                             : http://www.apple.com/quicktime/download/standalone.html  
CodecID_Compatible                       : isom/iso2/avc1/mp41  
File size                                : 11085451  
File size                                : 10.6 MiB  
File size                                : 11 MiB  
File size                                : 11 MiB  
File size                                : 10.6 MiB  
File size                                : 10.57 MiB  
Duration                                 : 297434  
Duration                                 : 4 min 57 s  
Duration                                 : 4 min 57 s 434 ms  
Duration                                 : 4 min 57 s  
Duration                                 : 00:04:57.434  
Duration                                 : 00:04:57:13  
Duration                                 : 00:04:57.434 (00:04:57:13)  
Overall bit rate mode                    : VBR  
Overall bit rate mode                    : Variable  
Overall bit rate                         : 298162  
Overall bit rate                         : 298 kb/s  
Frame rate                               : 30.000  
Frame rate                               : 30.000 FPS  
Frame count                              : 8923  
Stream size                              : 328932  
Stream size                              : 321 KiB (3%)  
Stream size                              : 321 KiB  
Stream size                              : 321 KiB  
Stream size                              : 321 KiB  
Stream size                              : 321.2 KiB  
Stream size                              : 321 KiB (3%)  
Proportion of this stream                : 0.02967  
HeaderSize                               : 40  
DataSize                                 : 10756527  
FooterSize                               : 328884  
IsStreamable                             : No  
File last modification date              : UTC 2021-04-12 10:12:36  
File last modification date (local)      : 2021-04-12 11:12:36  
Writing application                      : Lavf57.83.100  
Writing application                      : Lavf57.83.100  
  
Video  
Count                                    : 378  
Count of stream of this kind             : 1  
Kind of stream                           : Video  
Kind of stream                           : Video  
Stream identifier                        : 0  
StreamOrder                              : 0  
ID                                       : 1  
ID                                       : 1  
Format                                   : AVC  
Format                                   : AVC  
Format/Info                              : Advanced Video Codec  
Format/Url                               : http://developers.videolan.org/x264.html  
Commercial name                          : AVC  
Format profile                           : High@L4  
Format settings                          : CABAC / 4 Ref Frames  
Format settings, CABAC                   : Yes  
Format settings, CABAC                   : Yes  
Format settings, Reference frames        : 4  
Format settings, Reference frames        : 4 frames  
Internet media type                      : video/H264  
Codec ID                                 : avc1  
Codec ID/Info                            : Advanced Video Coding  
Duration                                 : 297434  
Duration                                 : 4 min 57 s  
Duration                                 : 4 min 57 s 434 ms  
Duration                                 : 4 min 57 s  
Duration                                 : 00:04:57.434  
Duration                                 : 00:04:57:13  
Duration                                 : 00:04:57.434 (00:04:57:13)  
Bit rate                                 : 167254  
Bit rate                                 : 167 kb/s  
Width                                    : 1920  
Width                                    : 1 920 pixels  
Height                                   : 1080  
Height                                   : 1 080 pixels  
Stored_Height                            : 1088  
Sampled_Width                            : 1920  
Sampled_Height                           : 1080  
Pixel aspect ratio                       : 1.000  
Display aspect ratio                     : 1.778  
Display aspect ratio                     : 16:9  
Rotation                                 : 0.000  
Frame rate mode                          : CFR  
Frame rate mode                          : Constant  
FrameRate_Mode_Original                  : VFR  
Frame rate                               : 30.000  
Frame rate                               : 30.000 FPS  
Frame count                              : 8923  
Color space                              : YUV  
Chroma subsampling                       : 4:2:0  
Chroma subsampling                       : 4:2:0  
Bit depth                                : 8  
Bit depth                                : 8 bits  
Scan type                                : Progressive  
Scan type                                : Progressive  
Bits/(Pixel*Frame)                       : 0.003  
Stream size                              : 6218374  
Stream size                              : 5.93 MiB (56%)  
Stream size                              : 6 MiB  
Stream size                              : 5.9 MiB  
Stream size                              : 5.93 MiB  
Stream size                              : 5.930 MiB  
Stream size                              : 5.93 MiB (56%)  
Proportion of this stream                : 0.56095  
Writing library                          : x264 - core 152 r2854 e9a5903  
Writing library                          : x264 core 152 r2854 e9a5903  
Encoded_Library_Name                     : x264  
Encoded_Library_Version                  : core 152 r2854 e9a5903  
Encoding settings                        : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00  
Codec configuration box                  : avcC  
  
Audio  
Count                                    : 280  
Count of stream of this kind             : 1  
Kind of stream                           : Audio  
Kind of stream                           : Audio  
Stream identifier                        : 0  
StreamOrder                              : 1  
ID                                       : 2  
ID                                       : 2  
Format                                   : AAC  
Format                                   : AAC LC  
Format/Info                              : Advanced Audio Codec Low Complexity  
Commercial name                          : AAC  
Format settings, SBR                     : No (Explicit)  
Format settings, SBR                     : No (Explicit)  
Format_AdditionalFeatures                : LC  
Codec ID                                 : mp4a-40-2  
Duration                                 : 297340  
Duration                                 : 4 min 57 s  
Duration                                 : 4 min 57 s 340 ms  
Duration                                 : 4 min 57 s  
Duration                                 : 00:04:57.340  
Duration                                 : 00:04:56:00  
Duration                                 : 00:04:57.340 (00:04:56:00)  
Bit rate mode                            : VBR  
Bit rate mode                            : Variable  
Bit rate                                 : 122099  
Bit rate                                 : 122 kb/s  
Maximum bit rate                         : 128000  
Maximum bit rate                         : 128 kb/s  
Channel(s)                               : 2  
Channel(s)                               : 2 channels  
Channel positions                        : Front: L R  
Channel positions                        : 2/0/0  
Channel layout                           : L R  
Samples per frame                        : 1024  
Sampling rate                            : 48000  
Sampling rate                            : 48.0 kHz  
Samples count                            : 14272320  
Frame rate                               : 46.875  
Frame rate                               : 46.875 FPS (1024 SPF)  
Frame count                              : 13912  
Compression mode                         : Lossy  
Compression mode                         : Lossy  
Stream size                              : 4538145  
Stream size                              : 4.33 MiB (41%)  
Stream size                              : 4 MiB  
Stream size                              : 4.3 MiB  
Stream size                              : 4.33 MiB  
Stream size                              : 4.328 MiB  
Stream size                              : 4.33 MiB (41%)  
Proportion of this stream                : 0.40938  
Title                                    : simple_aac  
Default                                  : Yes  
Default                                  : Yes  
Alternate group                          : 1  
Alternate group                          : 1

And the MediaConvert job description (ID: 1618087025011-n9fbdn, in case anyone from AWS is reading):

{
"Queue": "[removed]",
"UserMetadata": {
"contentItemId": "[removed]",
"mode": "preview",
"environment": "production"
},
"Role": "[removed]",
"Settings": {
"OutputGroups": [
{
"CustomName": "File Group",
"Outputs": [
{
"ContainerSettings": {
"Container": "MP4",
"Mp4Settings": {}
},
"VideoDescription": {
"Width": 1920,
"Height": 1080,
"CodecSettings": {
"Codec": "H_264",
"H264Settings": {
"MaxBitrate": 6000000,
"RateControlMode": "QVBR",
"QvbrSettings": {
"QvbrQualityLevel": 9
}
}
}
},
"AudioDescriptions": [
{
"CodecSettings": {
"Codec": "AAC",
"AacSettings": {
"VbrQuality": "MEDIUM_HIGH",
"RateControlMode": "VBR",
"CodingMode": "CODING_MODE_2_0",
"SampleRate": 48000
}
}
}
],
"NameModifier": "-preview"
}
],
"OutputGroupSettings": {
"Type": "FILE_GROUP_SETTINGS",
"FileGroupSettings": {
"Destination": "[removed]"
}
}
}
],
"Inputs": [
{
"AudioSelectors": {
"Audio Selector 1": {
"SelectorType": "TRACK"
}
},
"FileInput": "[removed]"
}
]
},
"AccelerationSettings": {
"Mode": "DISABLED"
},
"StatusUpdateInterval": "SECONDS_60",
"Priority": 0
}

Topics
Media Services
Tags
AWS Elemental MediaConvert
Language
English
rossng
asked 3 years ago943 views
12 Answers
0

Hi

Regarding this case, I would suggest you to submit a support case in AWS console. It is because we need more info for investigation. For example, your account ID, region, source file etc. Or you could provide those info to me via private message.

Regards
Michael

AWS
awsmicmic
answered 3 years ago
0

Hi Michael

It seems that there is no way for me to create a support case without paying for a technical support plan. It's a little odd that this is required to report what seems to be a bug in a service that I'm already paying for.

Could you confirm whether I am required to pay to have someone look at this issue?

Thanks
Ross

Edit: just seen your note about sending a private message. I will send you the details.

Edited by: rossng on Apr 13, 2021 7:04 AM

rossng
answered 3 years ago
0

Hello,

After running analysis on your file I was able to link to a known issue on MediaConvert which AWS engineers are currently working hard to address in future changes to the MediaConvert service.

We believe this issue is caused by variable framerate and how AWS Elemental MediaConvert handles this.

Workaround:
Using ffmpeg to convert the job from VFR to CFR.
ffmpeg -i sourcefile.mp4 -c:v copy -af aresample=async=1 outputfile.mp4

Take the output file and run this through MediaConvert.

Thank you for raising this issue on the AWS forums and apologies that you experienced this. Engineers are working hard on improving the service.

Matthew

AWS
AWS-User-2011750
answered 3 years ago
0

Thanks for the response. I look forward to this issue being resolved in MediaConvert 

rossng
answered 3 years ago
0

Good evening,
we are also noticing an audio-video sync issue of one frame.

Video codec: h264
Audio codec: AAC or WAV

StefanoLT
answered 3 years ago
0

we are still seeing this - has this been resolved by engineering, or are we seeing a new bug ? thanks

Jodi
answered 3 years ago
0

Also seeing this issue here and there, has this been addressed yet or not?

mangolytics-richard
answered 3 years ago
0

Hi StefanoLT,

Please provide the following information via private message so we can investigate further:

Your account ID
Region
Source file

Thanks,
Shaista

AWS
shaista-aws
answered 3 years ago
0

Hi jshow,

Please provide the following information via private message so we can investigate further:

Your account ID
Region
Source file

Thanks,
Shaista

AWS
shaista-aws
answered 3 years ago
0

Hi Richard,

Please provide the following information via private message so we can investigate further:

Your account ID
Region
Source file

Thanks,
Shaista

AWS
shaista-aws
answered 3 years ago
0

Hello, this issue has been fixed? I'm facing the same issue with an MP4 H.264 Video with Audio codec AAC

rePost-User-0338838
answered 2 years ago
0

I am experiencing the same issue. Who can I submit a sample to for investigation/advice?

Stu-R-User
answered 10 months ago

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