Posts by Bromor

Hello!

I am facing playback issues of videos (recorded by VDR) when seeking the video by BigStepForward (and sometimes also when using StepForward). After doing some consecutive BigStepForward steps video is broken into single frames showing up after some seconds or black screens. Audio plays for some seconds after a new frame/image is provided to TV but stops after some seconds. In between the loading cycle (100%) of kodi is showing during black screens like during buffering of streaming content. This failure symptom is repeating, playback does not recover to normal playback.

The same video file plays fine when starting from beginning or seeking the file by absolute position (giving the position with the number block during playback).

The file is stored on local disk, no network streaming.

Debug log: pastebin

Line 1445: Playback started

Line 2334: Start of pressing BigStepForward sequence

Additional information: screenshots

As solution I added pulseaudio in between and now audio is playing fine from TV.

Added to ~/.config/autostart.sh:

pactl load-module module-alsa-sink device="default"

Yes, but this only changes the sampling rate, not the format. No audio from TV with "fixed" output configuration with either 44.1 or 48 kHz.

Hello!

Background of my issue: I have a somewhat old TV which only supports 16 Bit and 20 Bit PCM audi input.

LibreELEC:~ # cat /proc/asound/card0/eld\#2.0
monitor_present         1
eld_valid               1
monitor_name            PHILIPS FTV
connection_type         HDMI
eld_version             [0x2] CEA-861D or below
edid_version            [0x3] CEA-861-B, C or D
manufacture_id          0xc41
product_id              0x0
port_id                 0x0
support_hdcp            0
support_ai              1
audio_sync_delay        0
speakers                [0x1] FL/FR
sad_count               2
sad0_coding_type        [0x1] LPCM
sad0_channels           2
sad0_rates              [0xe0] 32000 44100 48000
sad0_bits               [0x60000] 16 20
sad1_coding_type        [0x2] AC-3
sad1_channels           6
sad1_rates              [0xe0] 32000 44100 48000
sad1_max_bitrate        640000

Unfortunately something is going wrong somewhere and I do not get any audio from my TV in stock configuration. I assume there is a problem with the 20 Bit PCM format for my TV. By default, audio is passed to ALSA in 32 Bit format.

LibreELEC:~ # cat /proc/asound/card0/pcm3p/sub0/hw_params
access: RW_INTERLEAVED
format: S32_LE
subformat: STD
channels: 2
rate: 48000 (48000/1)
period_size: 2400
buffer_size: 9600

After some tries, i figured out that audio is playing fine from TV if passed as 16 Bit PCM format.

LibreELEC:~ # cat /proc/asound/card0/pcm3p/sub0/hw_params
access: RW_INTERLEAVED
format: S16_LE
subformat: STD
channels: 2
rate: 48000 (48000/1)
period_size: 6000
buffer_size: 24000

Now I am searching for any solution to convert the audi coming from Kodi to 16 Bit PCM format before passed to TV over HDMI. (Any solution welcome)

My approach was to convert die audio stream in the ALSA layer by a plug, so i configured ~/.config/asound.conf as follows (based on the description from alsa-project.org)

pcm_slave.sl3 {
    pcm "hw:0,3"
    format S16_LE
    channels 2
    rate 48000
}

pcm.complex_convert {
    type plug
    slave sl3
}

pcm.!default {
    type plug
    slave.pcm "complex_convert"
}

This works as expected at the ALSA layer and now a can play e.g. 24 Bit audio passed to ALSA default device by aplay and hear the sound from my TV.

LibreELEC:~ # aplay -v sample05.wav
Playing WAVE 'sample05.wav' : Signed 24 bit Little Endian in 3bytes, Rate 48000 Hz, Mono
Plug PCM: Route conversion PCM (sformat=S16_LE)
  Transformation table:
    0 <- 0
    1 <- 0
Its setup is:
  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S24_3LE
  subformat    : STD
  channels     : 1
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 24
  buffer_size  : 24000
  period_size  : 6000
  period_time  : 125000
  tstamp_mode  : NONE
  tstamp_type  : MONOTONIC
  period_step  : 1
  avail_min    : 6000
  period_event : 0
  start_threshold  : 24000
  stop_threshold   : 24000
  silence_threshold: 0
  silence_size : 0
  boundary     : 6755399441055744000
Slave: Hardware PCM card 0 'HDA Intel PCH' device 3 subdevice 0
Its setup is:
  stream       : PLAYBACK
  access       : MMAP_INTERLEAVED
  format       : S16_LE
  subformat    : STD
  channels     : 2
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 16
  buffer_size  : 24000
  period_size  : 6000
  period_time  : 125000
  tstamp_mode  : NONE
  tstamp_type  : MONOTONIC
  period_step  : 1
  avail_min    : 6000
  period_event : 0
  start_threshold  : 24000
  stop_threshold   : 24000
  silence_threshold: 0
  silence_size : 0
  boundary     : 6755399441055744000
  appl_ptr     : 0
  hw_ptr       : 

But in Kodi, the default ALSA device is not updated (still shows analog output and no audio on TV) and the HDMI selection as audio output still uses the 32 Bit format for ALSA. Also, my complex_convert alias (from asound.conf) is not showing as ALSA sink in the Kodi audi selection list.

Is it possible to use the complex_convert ALSA alias as audio sink for Kodi?

Other approach: Kodi selects audio sample format as AE_FMT_S32NE, is there a way to force it to AE_FMT_S16LE?

Kodi debug log

Any ideas how I can solve my issue?