Den 17.01.2024 00:54, skrev Andrew Randrianasulu:
ср, 17 янв. 2024 г., 02:07 Terje J. Hanssen <[email protected]>:
Den 16.01.2024 23:32, skrev Andrew Randrianasulu:
ср, 17 янв. 2024 г., 01:14 Andrew Randrianasulu
<[email protected]>:
ср, 17 янв. 2024 г., 01:04 Andrew Randrianasulu
<[email protected]>:
ср, 17 янв. 2024 г., 00:42 Terje J. Hanssen
<[email protected]>:
Den 16.01.2024 21:35, skrev Andrew Randrianasulu:
вт, 16 янв. 2024 г., 23:30 Terje J. Hanssen
<[email protected]>:
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.
=====
To supplement the earlier information with wikipedia's hdv audio
specification:
https://en.wikipedia.org/wiki/HDV#Specifications
Audio
Compression MPEG-1 Audio Layer II, PCM (HDV 720p)
MPEG-1 Audio Layer II (HDV 1080i)
Sampling frequency 48 kHz
Quantization 16 bits
Audio modes and data rate
MPEG-1 Part 3 AL 2 Stereo (2-channel) at 384 kbit/s (192 kbit/s per
channel);
optional MPEG-2 Part 3 AL 2 4-channel at 96 kbit/s per channel.
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..
=====
.2.1.8 Adaptive Multichannel Prediction
Adaptive multichannel prediction is used to reduce the inter-channel
redundancy. When using multichannel
prediction, the signals in the transmission channels T2..T4 are
predicted from the signals in the MPEG-1 compatible
part of the bit stream (Lo, Ro). Instead of the actual signals in a
subband group, the prediction error is transmitted,
together with predictor coefficients and delay compensation.
=======
from
https://courses.e-ce.uth.gr/CE401/tree_menu/tutorials/MPEG2/13818-3.pdf
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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