[Cin] HDV is really 4 channel?

[Andrew Randrianasulu]

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.
=====



>
>
>>
>>
>> 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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