fix 0x141a record parsing and add dante channel type detection
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
This commit is contained in:
Ian Gulliver
@@ -72,19 +72,44 @@ Zero offset = no more records.
|
||||
|
||||
### Subscription Record
|
||||
|
||||
Each record is 56+ bytes. The offset table points to record start.
|
||||
Two record formats exist, distinguished by marker position.
|
||||
|
||||
#### Format 1: 0x141c records (numbered audio/video channels)
|
||||
|
||||
```
|
||||
record+0x00: [40] record_header
|
||||
record+0x28: u16 0x0608 # marker
|
||||
record+0x2a: u16 0x0000
|
||||
record+0x00: u16 0x141c # record marker
|
||||
record+0x02: u16 channel_num # RX channel number
|
||||
record+0x04: u16 0x0000
|
||||
record+0x06: u16 0x0003
|
||||
record+0x08: u16 channel_num # repeated
|
||||
record+0x0a: u16 0x0000
|
||||
record+0x0c: u16 0x0000
|
||||
record+0x0e: u16 channel_type # 0x000f=audio, 0x000e=video
|
||||
...
|
||||
record+0x2c: u16 tx_ch_offset # absolute offset to TX channel name string
|
||||
record+0x2e: u16 tx_dev_offset # absolute offset to TX device name string
|
||||
record+0x30: [4] flags
|
||||
record+0x34: u32 0x02020000 # string marker
|
||||
record+0x38: ... inline_strings # (unreliable, use offsets above)
|
||||
```
|
||||
|
||||
**Channel type (at record+0x0e):**
|
||||
- `0x000f` = audio channel
|
||||
- `0x000e` = video channel
|
||||
|
||||
#### Format 2: 0x141a records (special channels: Video, Serial, USB)
|
||||
|
||||
```
|
||||
record+0x00: u16 0x141a # record marker
|
||||
record+0x02: u16 channel_num # e.g., 0x0009 = channel 9
|
||||
record+0x04: u16 ??
|
||||
record+0x06: u16 ??
|
||||
...
|
||||
record+0x2c: u16 tx_ch_offset # same position as 0x141c
|
||||
record+0x2e: u16 tx_dev_offset # same position as 0x141c
|
||||
```
|
||||
|
||||
These are video channels (Dante AV "Video" aggregate channel).
|
||||
|
||||
Both 0x141c and 0x141a records use the same offsets for tx_ch and tx_dev (+44 and +46).
|
||||
|
||||
**Subscription status:**
|
||||
- Both offsets non-zero = subscribed
|
||||
- Both offsets zero = unsubscribed
|
||||
@@ -126,9 +151,85 @@ Record at 0x0258 (RX ch 25):
|
||||
|
||||
1. Check magic=0x28, command=0x3400, status=0x8112
|
||||
2. Read 16 offsets from 0x12-0x31
|
||||
3. For each non-zero offset:
|
||||
- Read u16 at offset+0x2c (tx_ch_offset)
|
||||
- Read u16 at offset+0x2e (tx_dev_offset)
|
||||
- If both zero: skip (unsubscribed)
|
||||
- Else: read null-terminated strings at those offsets
|
||||
- RX channel = page_start + record_index
|
||||
3. For each non-zero offset, detect record format:
|
||||
- If offset+0x00 == 0x141c: Format 1 (numbered channel)
|
||||
- channel_type at offset+0x0e (0x000f=audio, 0x000e=video)
|
||||
- tx_ch_offset at offset+0x2c
|
||||
- tx_dev_offset at offset+0x2e
|
||||
- If offset+0x00 == 0x141a: Format 2 (special channel)
|
||||
- Assume video type
|
||||
- tx_ch_offset at offset+0x2c (same as 0x141c)
|
||||
- tx_dev_offset at offset+0x2e (same as 0x141c)
|
||||
4. If tx_ch_offset and tx_dev_offset are both zero: skip (unsubscribed)
|
||||
5. Read null-terminated strings at those offsets
|
||||
6. RX channel = page_start + record_index
|
||||
|
||||
---
|
||||
|
||||
## Additional Commands
|
||||
|
||||
### 0x2000 - TX Channel Info
|
||||
|
||||
Request args (6 bytes):
|
||||
```
|
||||
0x00: u16 0x0001
|
||||
0x02: u16 page_num
|
||||
0x04: u16 0x0000
|
||||
```
|
||||
|
||||
Response contains TX channel entries:
|
||||
```
|
||||
0x00: u16 channel_num
|
||||
0x02: u16 channel_type # see below
|
||||
0x04: u16 name_offset
|
||||
0x06: u16 unknown
|
||||
```
|
||||
|
||||
Observed channel_type values:
|
||||
- `0x0107` = audio channel (seen on MICS, SQ-7, speaker devices)
|
||||
- `0x0007` = possibly video or different encoding?
|
||||
|
||||
Sample rate `0xbb80` (48000) appears in responses.
|
||||
|
||||
### 0x3600 - TX Flow Info
|
||||
|
||||
Uses magic=0x28. Returns info about outgoing flows.
|
||||
|
||||
Response includes IP addresses of flow destinations.
|
||||
|
||||
---
|
||||
|
||||
## Multicast Group Ranges
|
||||
|
||||
Audio and video use different multicast IP ranges:
|
||||
- `239.69.x.x` - `239.71.x.x` = Dante audio multicast
|
||||
- `239.253.x.x` = Dante AV (video) multicast
|
||||
|
||||
---
|
||||
|
||||
## Channel Type Detection
|
||||
|
||||
**SOLVED**: Audio vs video channels are distinguished by the channel_type field at record+0x0e in 0x3400 responses:
|
||||
- `0x000f` = audio channel
|
||||
- `0x000e` = video channel
|
||||
|
||||
Dante AV devices (TX-*, RX-* naming convention) have both audio and video channels. The type must be checked per-channel, not per-device.
|
||||
|
||||
---
|
||||
|
||||
## Open Questions
|
||||
|
||||
### Other Channel Types
|
||||
|
||||
Video devices have additional channel types with marker 0x141a instead of 0x141c:
|
||||
- "Video" channels (the actual video stream)
|
||||
- "Serial" channels
|
||||
- "USB" channels
|
||||
|
||||
These use a different record structure. Need to decode the 0x141a record format.
|
||||
|
||||
### 0x2000 Channel Type Field
|
||||
|
||||
The 0x2000 response has a channel_type field at entry+0x02. Observed values:
|
||||
- `0x0007` seen on Ultimo X (audio devices)
|
||||
- Need to compare with video device 0x2000 responses
|
||||
|
||||
Reference in New Issue
Block a user