HEVC/AC3 TS stream won't play through TVH

C M

Currently using TVH with my HDHR Flex 4k for ATSC1 channels, all is working. I want to make use of the ATSC3 channels too though. I'm using VLC to test. I'm using Emby's FFMPEG 5.1 version (it has AC4 decode) to transcode audio from AC4 to AC3 while copying the HEVC video. I'm using the pipe: command in the mux's URL and I've messed with it a lot to troubleshoot but this is the most basic form: pipe:///usr/bin/ffmpeg -i http://192.168.1.10:5004/auto/v108.1 -c:v copy -c:a ac3 -b:a 640k -ac 6 -f mpegts pipe:1

My issue is that when I play the channel in VLC, I get no video or audio streams. In the TVHeadend status tab, the stream looks normal and the 'bandwidth' looks exactly as it should, like the data is flowing.

I tested the channel without the pipe through ffmpeg. This way I do get video in VLC but no audio, as expected since AC4 isn't supported.
I tested my pipe command from the terminal and instead of output to pipe:1, I outputted it to test.ts file. This file results in HEVC and AC3 (transcoded) and plays in VLC just fine.
I cannot understand what about the audio transcoded output that TVHeadend doesn't like. I tried transcoding to AAC instead of AC3 and got the same result. I've tried A LOT.

I can upload my sample file if anyone is willing to take a look. I am at the end of my knowledge here. Here is the ffprobe output of my transcoded sample that won't play:

Input #0, mpegts, from 'test.ts':
  Duration: 00:01:15.38, start: 1.400000, bitrate: 6906 kb/s
  Program 1
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
  Stream #0:0[0x100]: Video: hevc (Main 10) (HEVC / 0x43564548), yuv420p10le(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 59.94 fps, 59.94 tbr, 90k tbn
  Stream #0:1[0x101](eng): Audio: ac3 (AC-3 / 0x332D4341), 44100 Hz, 5.1(side), fltp, 640 kb/s

C M

Just in case someone has time to check the sample file. It is HEVC/AC3. This plays just fine in VLC. TVHeadend looks like it's streaming, judging by the "Bandwidth" in the status tab of TVH, plus the ffmpeg logs. But when piping through TVHeadend, VLC gets no video and no Audio streams.
What about this stream/file is TVH not liking?
https://www.dropbox.com/scl/fi/pfsmfyry87f3ff448fj0t/test.ts?rlkey=kqqvtka8bxwp95ufkxlk4bw3t&e=1&st=6uwaopqt&dl=1

Thanks for any input. If I can post a more detailed ffprobe output that could be helpful, I will do that.

ukn_unknown

If you compile with libav and ffmpeg_static you can try to convert with tvh (natively) from AC4 to AAC. I see many places in source code with "AC4" ; maybe is working. If you need help you should upload a small sample (30 sec) of video saved with 'pass' profile into a *.ts file.

C M

ukn_unknown Thank you! I will look into that. I remember seeing that ffmpeg added support for passthrough of ac4 but I was not aware of the decode to AAC.

ukn_unknown If you need help you should upload a small sample (30 sec) of video saved with 'pass' profile into a *.ts file.
Would this suffice? It's only 62mb and TVH just refuses to pass the sample or the stream, VLC plays both directly though.

https://www.dropbox.com/scl/fi/pfsmfyry87f3ff448fj0t/test.ts?rlkey=kqqvtka8bxwp95ufkxlk4bw3t&e=1&st=6uwaopqt&dl=1

C M

ukn_unknown If you compile with libav and ffmpeg_static you can try to convert with tvh (natively) from AC4 to AAC. I see many places in source code with "AC4" ; maybe is working.

ffmpeg 7.1 static version:
[aist#0:1/ac4 @ 0x5e633df856c0] Decoding requested, but no decoder found for: ac4

ukn_unknown File is not available.

Oops. I think the file is actually okay though, I think the issue is piping ffmpeg to TVH.
https://www.dropbox.com/scl/fi/66ytz3ecl2bokmw3x2b7q/test.ts?rlkey=6jbt59uencvodt6yfd8oump5i&st=57hmstlw&dl=1

Tony Wagner

Take your TVHeadend stream URL (the one you are trying to play in VLC) and try to pass it as input to ffmpeg and see what it reports.

I use one of the Docker containers to handle the AC4 conversion and they play fine through TVHeadend: johnb-7/hdhr-ac4

C M

Tony Wagner Take your TVHeadend stream URL (the one you are trying to play in VLC) and try to pass it as input to ffmpeg and see what it reports.

Good call. I will.

Tony Wagner I use one of the Docker containers to handle the AC4 conversion and they play fine through TVHeadend:

I played around with that but the issue was that it doesn't support specifying the tuner, only 'auto'. On auto, if two atsc1 channels play first, it puts them on tuner0 and tuner1. Those are the two that play ATSC3. There might be a workaround, I thought the HDHR should occupy the atsc1 tuners first but it didn't.

ukn_unknown

C M
File is not available.
"This item was deleted" 🙁

Tony Wagner

Can you pipe an ATSC 1 stream through TVHeadend via ffmpeg? Just making sure it’s not something general about your pipe that isn’t working.

C M

Tony Wagner Can you pipe an ATSC 1 stream through TVHeadend via ffmpeg? Just making sure it’s not something general about your pipe that isn’t working.

Yes. And I can transcode audio with ffmpeg if I want. With the ATSC3 channel, the url going straight to HDHR, I do get HEVC, but it drops the AC4 as expected. I just fully expect this output from the emby ffmpeg should pass through since it's hevc and ac3, but instead the video no longer even plays.

C M

Tony, thanks for the pointer. I'm just double checking and I can no longer use the pipe:///usr/bin/ffmpeg in the mux for atsc1 either. I guess I've broken something else. It's doing the same thing, VLC holds the stream open and plays nothing, nothing is in the codec tab of VLC. TVH status says it's using the right amount of bandwidth and the connection stays up though.

ukn_unknown

C M Oops. I think the file is actually okay though, I think the issue is piping ffmpeg to TVH.
https://www.dropbox.com/scl/fi/66ytz3ecl2bokmw3x2b7q/test.ts?rlkey=6jbt59uencvodt6yfd8oump5i&st=57hmstlw&dl=1

Can you upload also a file as it is at the input (with AC4) collected with profile 'pass'? I see the file above is the output (with AC3)