[Cin] HDV is really 4 channel?

[Andrew Randrianasulu]

ср, 17 янв. 2024 г., 00:42 Terje J. Hanssen <terjejhanssen at gmail.com>:

>
>
> Den 16.01.2024 21:35, skrev Andrew Randrianasulu:
>
>
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> 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!



>
>
> 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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