[FFmpeg-user] TEE muxer and missing mpegts_flags

Alex Molon alex.molon at vision247.com
Wed Jun 26 15:26:31 EEST 2019

Hi Gyan,

Actually most of the errors were made just because I wrote the command in the email rather than copying the command I was issuing.

Actually I was already using columns and not commas, but definitely the error was in how I was using the -latm option.

I though latm was related to the previous flag option, so I didn't think to suffix :a:0

Your help was extremely clarifying, thanks a lot.

I've end up doing this:

/usr/src/ffmpeg-4.1.3/ffmpeg -v verbose -hwaccel cuvid -c:v h264_cuvid -i "udp://" -vf scale_npp=1280:720:format=yuv420p,hwdownload -map 0:v -map 0:a -map 0:a -r 25 -g 50 -c:v h264_nvenc -c:a libfdk_aac -flags:a:0 +global_header -latm:a:0 1 -profile:a:0 aac_he -c:a:1 libfdk_aac -f tee "[f=mpegts:mpegts_flags=latm:select=\'0,1\']udp://|[f=mpegts:select=\'0,2\']udp://"

And actually now does exactly what I need.

Thank you, really


-----Original Message-----
From: ffmpeg-user [mailto:ffmpeg-user-bounces at ffmpeg.org] On Behalf Of Gyan
Sent: 26 June 2019 12:38
To: ffmpeg-user at ffmpeg.org
Subject: Re: [FFmpeg-user] TEE muxer and missing mpegts_flags

On 26-06-2019 03:56 PM, Alex Molon wrote:
> Hi All,
> I need to live encode a video and send it to two separate UDP outputs with different settings, since the only difference is  the audio track, I was thinking to use the TEE muxer but I don't know how to pass a mpegts_flag
> At the moment I'm using two different processes, but I'm wasting CPU resources:
> Process 1: ffmpeg -i input -c:v libx264 -c:a libfdk_aac -flags:a +global_header -latm 1 -profile:a aac_he -mpegts_flags latm -f mpegts udp://
> Process 2: ffmpeg -i input -c:v libx264 -c:a libfdk_aac -f mpegts udp://
> So I've tried with something like this:
> ffmpeg -i input -map 0:v -map 0:a -map 0:a -c:v libx264 -c:a libfdk_aac -flags:a:0  +global_header -latm 1 -profile:a: aac_he -f tee "[f=mpegts:mpegts_flags=latm,select=\'0,1\']udp://|[f=mpegts,select=\'0,2\']udp://"
> but it sems the option mpegts_flags=latm is totally ignored since I can see this error:
> [LATM/LOAS muxer @ 0x55f4f9d038c0] Muxing MPEG-4 AOT 21 in LATM is not supported
> [tee @ 0x55f4f6689600] Slave '[f=mpegts:mpegts_flags=latm:select='0,4']udp://': error writing header: Invalid data found when processing input
> Where am I wrong?
> Any suggestion?

A few things are wrong. Options for a slave muxer are separated by a 
colon ':'  so




Same for



-latm 1 -profile:a: aac_he

applies these options to both audio encodes.

Change to

-latm:a:0 1 -profile:a:0 aac_he


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