[Cin] HDV is really 4 channel?
Terje J. Hanssen
terjejhanssen at gmail.com
Wed Jan 17 00:07:57 CET 2024
Den 16.01.2024 23:32, skrev Andrew Randrianasulu:
>
>
> 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
> <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 :)
>
Yeah, I saw some of the forum threads and had a look on the sample files.
For me they the ffprobe outputs were identical with my own hdv.m2t files.
I think as Mullen wrote, the limit for miniDV or HDV tapes was utilized
for 1080i HD2 with 25 Mbps.
Only the 720p HD2 format with 19 Mbps had PCM tracs free for later use.
Maybe other camcorders..
Possibly file storage on other disc media could be utilized for larger
bandwidth.
But I cannot see it was mentioned for the targeted camcorder disc recorder
https://www.bhphotovideo.com/c/product/461819-REG/Sony_HVRDR60_HVRDR60_Hard_Disk_Recording.html
>
>
>
>
>
>> 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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