Loss of audio on recorded BBC HD channel transport streams

[Mintman]

Hi When I use fortherecord (http://www.4therecord.eu/) to record HD streams from the BBC HD channel (specifically Top Gear) I get audio playback for the section where it's recording early to avoid missing the start of the show but when it goes to the BBC HD logo I lose sound. I know it has recorded fine because if I switch to the audio track for the visually impaired and then back to the normal audio track I get full sound again. Also if I skip through the stream I lose sound until I repeat the process.
here is the output from the messages window set to verbosity 2 as soon after starting the clip as I can start it, the sound vanishes at the point the first message appears and then I cycle between the two audio streams to fix it.

if needed I can upload the start of the troubling stream if someone can tell me where to send it, anyone have any suggestions
faad warning: unknown channel ordering
faad warning: unknown channel ordering
faad warning: unknown channel ordering
main debug: removing module "scaletempo"
main debug: removing module "ugly_resampler"
aout_directx debug: closing audio device
aout_directx debug: DirectSoundThread exiting
main debug: thread ended
main debug: thread times: real 0m27.822434s, kernel 0m0.000000s, user 0m0.000000s
main debug: removing module "aout_directx"
main debug: removing module "audio_format"
main debug: removing module "float32_mixer"
main error: incompatible audio channels count with layout mask
main error: failed to create audio output
main debug: VoutDisplayEvent 'mouse button' 2 t=8
main debug: VoutDisplayEvent 'mouse button' 2 t=9
main debug: auto hidding mouse
main debug: control type=13
main debug: looking for decoder module: 34 candidates
main debug: using decoder module "faad"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: looking for packetizer module: 21 candidates
packetizer_mpeg4audio debug: running MPEG4 audio packetizer
packetizer_mpeg4audio debug: no decoder specific info, must be an ADTS or LOAS stream
main debug: using packetizer module "packetizer_mpeg4audio"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: thread started
main debug: thread (decoder) created at priority 2 (input/decoder.c:301)
main debug: thread times: real 0m37.265596s, kernel 0m0.000000s, user 0m0.031200s
main debug: removing module "faad"
main debug: killing decoder fourcc `mp4a', 0 PES in FIFO
main debug: releasing aout
main debug: removing module "packetizer_mpeg4audio"
packetizer_mpeg4audio debug: detected LOAS format
packetizer_mpeg4audio info: AAC channels: 1 samplerate: 24000
faad warning: decoded zero sample
faad debug: AAC SBR (channels: 2, samplerate: 48000)
main debug: reusing aout
main info: Reparenting an object is dangerous (004c7c58 -> 004c7c58)!
main debug: looking for audio output module: 4 candidates
aout_directx debug: Opening DirectSound Audio Output
aout_directx debug: found device: Primary Sound Driver
aout_directx debug: found device: Speakers (High Definition Audio Device)
aout_directx debug: found device: Digital Audio (S/PDIF) (High Definition Audio Device)
aout_directx debug: found device: AMD HDMI Output (AMD High Definition Audio Device)
aout_directx debug: found device: Digital Audio (HDMI) (High Definition Audio Device)
aout_directx debug: device supports 2 channels (DEFAULT!)
aout_directx debug: device supports 1 channel
aout_directx debug: Windows says your SpeakerConfig is stereo
aout_directx debug: creating DirectSoundThread
main debug: thread (DirectSound Notification Thread) created at priority 15 (directx.c:321)
main debug: thread started
main debug: using audio output module "aout_directx"
aout_directx debug: DirectSoundThread ready
main debug: TIMER module_need() : 10.000 ms - Total 10.000 ms / 1 intvls (Avg 10.000 ms)
main debug: output 's16l' 48000 Hz Stereo frame=1 samples/4 bytes
main debug: mixer 'f32l' 48000 Hz Stereo frame=1 samples/8 bytes
main debug: filter(s) 'f32l'->'s16l' 48000 Hz->48000 Hz Stereo->Stereo
main debug: looking for audio filter module: 13 candidates
audio_format debug: f32l->s16l, bits per sample: 32->16
main debug: using audio filter module "audio_format"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: found a filter for the whole conversion
main debug: looking for audio mixer module: 3 candidates
main debug: using audio mixer module "float32_mixer"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: input 'f32l' 48000 Hz Stereo frame=1 samples/8 bytes
main debug: looking for audio filter module: 1 candidate
scaletempo debug: format: 48000 rate, 2 nch, 4 bps, fl32
scaletempo debug: params: 30 stride, 0.200 overlap, 14 search
scaletempo debug: 1.000 scale, 1440.000 stride_in, 1440 stride_out, 1152 standing, 288 overlap, 672 search, 2400 queue, fl32 mode
main debug: using audio filter module "scaletempo"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: filter(s) 'f32l'->'f32l' 52800 Hz->48000 Hz Stereo->Stereo
main debug: looking for audio filter module: 13 candidates
main debug: using audio filter module "ugly_resampler"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: found a filter for the whole conversion
main debug: VoutDisplayEvent 'mouse button' 2 t=8
main debug: VoutDisplayEvent 'mouse button' 2 t=9
main warning: output date isn't PTS date, requesting resampling (43425)
main warning: buffer is 43423 late, triggering upsampling
main debug: auto hidding mouse
main debug: control type=13
main debug: looking for decoder module: 34 candidates
main debug: using decoder module "faad"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: looking for packetizer module: 21 candidates
packetizer_mpeg4audio debug: running MPEG4 audio packetizer
packetizer_mpeg4audio debug: no decoder specific info, must be an ADTS or LOAS stream
main debug: using packetizer module "packetizer_mpeg4audio"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: thread (decoder) created at priority 2 (input/decoder.c:301)
main debug: thread started
main warning: received buffer in the future
main debug: thread times: real 0m3.807562s, kernel 0m0.015600s, user 0m0.000000s
main debug: removing module "faad"
main debug: killing decoder fourcc `mp4a', 0 PES in FIFO
main debug: removing module "scaletempo"
main debug: removing module "ugly_resampler"
aout_directx debug: closing audio device
aout_directx debug: DirectSoundThread exiting
main debug: thread ended
main debug: thread times: real 0m3.572559s, kernel 0m0.000000s, user 0m0.000000s
main debug: removing module "aout_directx"
main debug: removing module "audio_format"
main debug: removing module "float32_mixer"
main debug: releasing aout
main debug: removing module "packetizer_mpeg4audio"
packetizer_mpeg4audio debug: detected LOAS format
packetizer_mpeg4audio info: AAC channels: 6 samplerate: 48000
faad warning: decoded zero sample
main debug: reusing aout
main info: Reparenting an object is dangerous (004c7c58 -> 004c7c58)!
main debug: looking for audio output module: 4 candidates
aout_directx debug: Opening DirectSound Audio Output
aout_directx debug: found device: Primary Sound Driver
aout_directx debug: found device: Speakers (High Definition Audio Device)
aout_directx debug: found device: Digital Audio (S/PDIF) (High Definition Audio Device)
aout_directx debug: found device: AMD HDMI Output (AMD High Definition Audio Device)
aout_directx debug: found device: Digital Audio (HDMI) (High Definition Audio Device)
aout_directx debug: device supports 5.1 channels
aout_directx debug: device supports 4 channels
aout_directx debug: device supports 2 channels
aout_directx debug: device supports 1 channel
aout_directx debug: Windows says your SpeakerConfig is stereo
aout_directx debug: creating DirectSoundThread
main debug: thread (DirectSound Notification Thread) created at priority 15 (directx.c:321)
main debug: thread started
main debug: using audio output module "aout_directx"
aout_directx debug: DirectSoundThread ready
main debug: TIMER module_need() : 12.000 ms - Total 12.000 ms / 1 intvls (Avg 12.000 ms)
main debug: output 's16l' 48000 Hz Stereo frame=1 samples/4 bytes
main debug: mixer 'f32l' 48000 Hz Stereo frame=1 samples/8 bytes
main debug: filter(s) 'f32l'->'s16l' 48000 Hz->48000 Hz Stereo->Stereo
main debug: looking for audio filter module: 13 candidates
audio_format debug: f32l->s16l, bits per sample: 32->16
main debug: using audio filter module "audio_format"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: found a filter for the whole conversion
main debug: looking for audio mixer module: 3 candidates
main debug: using audio mixer module "float32_mixer"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: input 'f32l' 48000 Hz 3F2R/LFE frame=1 samples/24 bytes
main debug: looking for audio filter module: 1 candidate
scaletempo debug: format: 48000 rate, 2 nch, 4 bps, fl32
scaletempo debug: params: 30 stride, 0.200 overlap, 14 search
scaletempo debug: 1.000 scale, 1440.000 stride_in, 1440 stride_out, 1152 standing, 288 overlap, 672 search, 2400 queue, fl32 mode
main debug: using audio filter module "scaletempo"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: filter(s) 'f32l'->'f32l' 48000 Hz->48000 Hz 3F2R/LFE->Stereo
main debug: looking for audio filter module: 13 candidates
main debug: using audio filter module "simple_channel_mixer"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: found a filter for the whole conversion
main debug: filter(s) 'f32l'->'f32l' 52800 Hz->48000 Hz Stereo->Stereo
main debug: looking for audio filter module: 13 candidates
main debug: using audio filter module "ugly_resampler"
main debug: TIMER module_need() : 0.000 ms - Total 0.000 ms / 1 intvls (Avg 0.000 ms)
main debug: found a filter for the whole conversion
main warning: output date isn't PTS date, requesting resampling (44047)
main warning: buffer is 44047 late, triggering upsampling
main debug: auto hidding mouse
main debug: auto hidding mouse
main warning: resampling stopped after 9068000 usec (drift: 495)
main debug: auto hidding mouse

[Lotesdelere]

It might be because the number of audio channels is changing:

Code: Select all

packetizer_mpeg4audio debug: detected LOAS format packetizer_mpeg4audio info: AAC channels: 1 samplerate: 24000 faad warning: decoded zero sample faad debug: AAC SBR (channels: 2, samplerate: 48000) ... packetizer_mpeg4audio debug: detected LOAS format packetizer_mpeg4audio info: AAC channels: 6 samplerate: 48000 faad warning: decoded zero sample

Please could you upload a short sample of a file showing this issue ?
I suggest to use Multiupload.com, so it will upload the file for you to several other hosts, and then post the link to the file here.

[Mintman]

Hi Lotesdelere,

I've uploaded the first 150Mb of this stream. You can access it here:

http://www.multiupload.com/8NH4CGB03X

I've confirmed that it also shows the same behavior. In addition I have noticed some other peculiarities with the stream, whilst the seek bar moves in accordance with the position in time of the current frame in the stream, the current position is always 00:00:00/00:00:00 and if you seek outside regions with the same audio channel count you lose all audio until you cycle between the visually impaired audio track (1) and the English audio track (0).

hope this helps

[fa2k]

Hi, I have the same problem with a different TV channel, recorded using Mythtv. I wanted to play it in VLC to get the headphone spatialization effect. After the audio changes, VLC outputs 5.1 surround to the OS and I only hear the front channels in the headphones. The Audio->Channels option is grayed out. It's probably not necessary, but I uploaded a file as well: http://www.fa2k.net/misc/vlc_audio.mpg . The number of channels changes from stereo to 5.1 at approx. 0:25 . I get lots of "faad warning: unknown channel ordering".

[Jean-Baptiste Kempf]

You should probably file a bug.

[philr3]

Did a bug get raised for this issue?

I think I'm experiencing the same problem with VLC 2.0.5 on Windows, playing TS files recorded with ARGUS TV from Freeview HD in the UK. Each time the audio switches from stereo to 5.1, the audio channels get messed up. I have a 5.1 speaker system. It sounds like the two rear channels are being played on both the front and rear speakers. The front centre speaker seems to be silent. The subwoofer just makes buzzing sounds at various different frequencies.

Switching to the visually impaired audio track and back fixes the problem.

I've posted the log from the time of the change of audio format at http://pastebin.com/TuqG6m3r. The 'faad warning: unknown channel ordering' message at the ends repeats continuously. I can upload a sample video if anyone is interested.

[Jean-Baptiste Kempf]

Please try with 2.1.0 and file a bugreport, indeed...

[philr3]

With the latest nightly 2.1.0 builds, the audio now intermittently drops/cuts out when audio switches from stereo to 5.1.

I have filed bug #8393 for this issue and uploaded a sample file to the samples server.

[Jean-Baptiste Kempf]

So, it is a bit better in 2.1, right?

[philr3]

I'd actually say it is worse in 2.1. The audio drop outs I mentioned are nearly continuous (probably at least 90% of the time). When the sound is audible, the front centre channel is still missing. The front left and right and subwoofer are possibly okay though, but I'm not sure.

If I cycle to the visually impaired audio track and back to the main audio track, the sound ends up significantly out of synchronization with the pictures (the sound is at least a second behind the picture).