[Cin] HDV is really 4 channel?

Tue Jan 16 23:32:44 CET 2024

ср, 17 янв. 2024 г., 01:14 Andrew Randrianasulu <randrianasulu at gmail.com>:

>
>
> ср, 17 янв. 2024 г., 01:04 Andrew Randrianasulu <randrianasulu at gmail.com>:
>
>>
>>
>> ср, 17 янв. 2024 г., 00:42 Terje J. Hanssen <terjejhanssen at gmail.com>:
>>
>>>
>>>
>>> Den 16.01.2024 21:35, skrev Andrew Randrianasulu:
>>>
>>>
>>>
>>> вт, 16 янв. 2024 г., 23:30 Terje J. Hanssen <terjejhanssen at gmail.com>:
>>>
>>>>
>>>>
>>>> Den 16.01.2024 20:23, skrev Andrew Randrianasulu:
>>>>
>>>> https://trac.ffmpeg.org/ticket/1258
>>>>
>>>> see attached to this ticket  modded decoder ...
>>>>
>>>> I wonder if Terje's audio really 4ch? if so,may be we can decode it to
>>>> 4* wav first, then encode them correctly to bluray lpcm / dvd pcm / ac3 ...
>>>>
>>>>
>>>>
>>>> I did leave out some "empty channels" to simplify and clean up the
>>>> post. Here are the full ffprobe output for the HDV source (mediainfo was
>>>> complete):
>>>>
>>>
>>>
>>> well, this ticket still open, so ffmpeg tools do not know yet about this
>>> .. extension? It decodes in compat stereo mode. I attached fixed decoder to
>>> this ticket, it will be interesting if you just run ffmpeg acodec copy
>>> command and then compile and run decoder on it .. it may decode to 4 files!
>>> But not sure how it all was arranged when it comes to microphones ...? Does
>>> camera contain 4 of them? or you were supposed to connect your own array?
>>>
>>>
>>> Well, I think Steve Mullen's handbook for Sony FX7 (mine) and V1 clarify
>>> there is only two audo channels on my FX7::
>>>
>>>    - There is two types of HDV: HD1/720p (19 Mbps) and HD2/1080i /25
>>>    Mbps) and Canon's 1080p24.
>>>    - HD1 is recorded to DV tape using only the DV video segment. The
>>>    PCM audio segment is open for future use.
>>>    - HD2 is recorded to DV tape using both the DV video segment and the
>>>    PCM audio segment. A small Subcode (ITI) segment holds data such
>>>    - as timecode. Because no PCM audio segments are available, HD2
>>>    cannot carry record PCM audio.
>>>    - MPEG-1 Audio:
>>>    - Both HD1 and HD2 support two audio channels of audio signals that
>>>    are digitized with a 48kHz at 16-bit quantization and compressed to
>>>    - 384kbps by MPEG-1 Audio Layer 2 encoding. ProHD adds two-channel
>>>    PCM audio thus creating a format that can carry four independent
>>>    - channels of audio. (See Chapter 2 for an in-depth introduction to
>>>    MPEG-1 audio.)
>>>
>>>
>> yeah, seems to be rarely supported on HDV cameras, see
>>
>> https://forum.blackmagicdesign.com/viewtopic.php?f=33&t=171688
>>
>> but still!
>>
>
>
> https://ieba.wordpress.com/2008/01/21/hdv-grows-up-sonys-hvr-s270-and-hvr-z7/
>
> =====
> *4-Channel Audio*
> The HDV specification, like the DV specification, has allowed for
> four-channel audio recording from the outset. Few cameras took advantage of
> it, and when they did, it was an add-on that did not maintain full balanced
> audio throughout. Though the smaller Sony HVR-Z7 records only two channels
> of audio, the larger HVR-S270 has two XLR inputs in the front of the
> camcorder and two XLR inputs on the back of the camcorder. Each one has a
> separate audio level control and an automatic level control switch on the
> side of the camcorder.
> =====
>

and samples:

https://forum.doom9.org/archive/index.php/t-125966-p-46.html

=====

As you can see 4 channel audio is part of the HDV format. I am not sure if
there are actually 2 audiostreams or only 1. There is no way I can check
this because the camera itself only outputs the 4 ch and no 2 ch. But the
computer will only play a 2 ch. But when you compare the MediaInfo audio
information with the specs I expect that there are 2 audio stream just like
eac3to detects. It would be very very nice if HDV support can be integrated
into eac3to because many professional cameramen are looking for an solution.

Currently eac3to extracts the m2v and 2ch audio stream fine. Only the 4
channel stream isn't detected nor extracted. I uploaded 2 sample to my
server for analysis:
http://tools.twanwintjes.nl/uploads/temp/00_0001_2010-11-07_153401.M2T (49
seconds / 152MB) - Right Click --> Save As
http://tools.twanwintjes.nl/uploads/temp/00_0002_2010-11-07_214302.M2T (44
seconds / 137MB) - Right Click --> Save As

====

yes, files still there :)

>
>
>>
>>
>>>
>>>
>>> ffprobe -hide_banner hdv07_05.m2t
>>>> [mpeg2video @ 0x55d58a968340] Invalid frame dimensions 0x0.
>>>>     Last message repeated 7 times
>>>> [mpegts @ 0x55d58a93e580] Could not find codec parameters for stream 2
>>>> (Unknown: none ([160][0][0][0] / 0x00A0)): unknown codec
>>>> Consider increasing the value for the 'analyzeduration' (0) and
>>>> 'probesize' (5000000) options
>>>> [mpegts @ 0x55d58a93e580] Could not find codec parameters for stream 3
>>>> (Unknown: none ([161][0][0][0] / 0x00A1)): unknown codec
>>>> Consider increasing the value for the 'analyzeduration' (0) and
>>>> 'probesize' (5000000) options
>>>> Input #0, mpegts, from 'hdv07_05.m2t':
>>>>   Duration: 00:06:58.27, start: 3276.528000, bitrate: 25626 kb/s
>>>>   Program 100
>>>>   Stream #0:0[0x810]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002),
>>>> yuv420p(tv, bt709, top first), 1440x1080 [SAR 4:3 DAR 16:9], 25000 kb/s, 25
>>>> fps, 25 tbr, 90k tbn, 50 tbc
>>>>     Side data:
>>>>       cpb: bitrate max/min/avg: 25000000/0/0 buffer size: 7340032
>>>> vbv_delay: N/A
>>>>   Stream #0:1[0x814]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz,
>>>> stereo, fltp, 384 kb/s
>>>>   Stream #0:2[0x815]: Unknown: none ([160][0][0][0] / 0x00A0)
>>>>   Stream #0:3[0x811]: Unknown: none ([161][0][0][0] / 0x00A1)
>>>> Unsupported codec with id 0 for input stream 2
>>>> Unsupported codec with id 0 for input stream 3
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
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