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V4L/DVB (4193): Update cx2341x fw encoding API doc.

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Based on recent tests it turned out that some features are not implemented.
This has now been documented.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Hans Verkuil 2006-06-18 14:56:12 -03:00 • committed by Mauro Carvalho Chehab
parent 18318e0004
commit 54f577b7f4
1 changed files with 18 additions and 2 deletions
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20
Documentation/video4linux/cx2341x/fw-encoder-api.txt
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@ -100,13 +100,20 @@ Param[1]
Name CX2341X_ENC_SET_BIT_RATE Name CX2341X_ENC_SET_BIT_RATE
Enum 149/0x95 Enum 149/0x95
Description Description
Assign average video stream bitrate. Assign average video stream bitrate. Note on the last three params:
Param[3] and [4] seem to be always 0, param [5] doesn't seem to be used.
Param[0] Param[0]
0=variable bitrate, 1=constant bitrate 0=variable bitrate, 1=constant bitrate
Param[1] Param[1]
bitrate in bits per second bitrate in bits per second
Param[2] Param[2]
peak bitrate in bits per second, divided by 400 peak bitrate in bits per second, divided by 400
Param[3]
Mux bitrate in bits per second, divided by 400. May be 0 (default).
Param[4]
Rate Control VBR Padding
Param[5]
VBV Buffer used by encoder
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
@ -115,10 +122,11 @@ Enum 151/0x97
Description Description
Setup the GOP structure Setup the GOP structure
Param[0] Param[0]
GOP size GOP size (maximum is 34)
Param[1] Param[1]
Number of B frames between the I and P frame, plus 1. Number of B frames between the I and P frame, plus 1.
For example: IBBPBBPBBPBB --> GOP size: 12, number of B frames: 2+1 = 3 For example: IBBPBBPBBPBB --> GOP size: 12, number of B frames: 2+1 = 3
Note that GOP size must be a multiple of (B-frames + 1).
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
@ -241,6 +249,9 @@ Name CX2341X_ENC_SET_STREAM_TYPE
Enum 185/0xB9 Enum 185/0xB9
Description Description
Assign stream type Assign stream type
Note: Transport stream is not working in recent firmwares.
And in older firmwares the timestamps in the TS seem to be
unreliable.
Param[0] Param[0]
0=Program stream 0=Program stream
1=Transport stream 1=Transport stream
@ -278,6 +289,8 @@ Description
'01' Layer III '01' Layer III
'00' Undefined '00' Undefined
This discrepancy may indicate a possible error in the documentation. This discrepancy may indicate a possible error in the documentation.
Testing indicated that only Layer II is actually working, and that
the minimum bitrate should be 192 kbps.
Param[0] Param[0]
Bitmask: Bitmask:
0:1 '00' 44.1Khz 0:1 '00' 44.1Khz
@ -313,6 +326,9 @@ Param[0]
'01'=JointStereo '01'=JointStereo
'10'=Dual '10'=Dual
'11'=Mono '11'=Mono
Note: testing seems to indicate that Mono and possibly
JointStereo are not working (default to stereo).
Dual does work, though.
10:11 Mode Extension used in joint_stereo mode. 10:11 Mode Extension used in joint_stereo mode.
In Layer I and II they indicate which subbands are in In Layer I and II they indicate which subbands are in