Migration Guide - Axis Communications
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1. cgi io input cgi F ae janiinsogs Jio output cgi Replaced by axis cgi io ports cgi Image and Video bitmap lt camera gt image bmp jpg lt camera gt image jpg mjpg lt camera gt video mjpg MPEG 4 API mpeg4 lt n gt media amp Replaced by axis media media amp Ahenlata nathe ODSO ete p arns view operator admin Rev 1 04 Last updated 23 01 2009 17 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 9 Axis H 264 Migration Experiences This section describes how Axis implemented support for H 264 in AXIS Camera Station 3 x and points out the standard documents where communications protocols video and audio formats are described To enable basic H 264 streaming 5 steps were taken Set up a HTTP GET tunnel to establish a connection to the camera H 264 specific information in the SDP data Support H 264 de packetization of packetized RTP packets Identify H 264 frame types Enable keep alive to keep RTSP sessions connected EWN Step 1 Set up a HTTP GET tunnel Axis chose to establish the connection to the camera using RTSP over HTTP the Apple QuickTime streaming technology Axis design with separate modules for data transfer RTSP and network connection enables a smooth switch to other protocols only a single module must be changed to make the system communicate over UDP instead To be able to re use the architecture already present2. gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide firmware 5 xx Note that the available video and audio formats may vary between products Axis products are designed with separate modules for data transfer and network connection The separate modules permit easy switching between for example the TCP and UDP transport protocols The AAC format streamed via HTTP over TCP is non standard Figure 1 Video and audio formats streaming and transport protocols supported by Axis firmware 5 xx Yellow boxes indicate options new in 5 xx 2 1 1 ISMA standard ISMA the Internet Streaming Media Alliance http www isma tv publishes technical specifications to integrate multimedia standards and facilitate interoperability between different clients and servers when distributing media over a network Axis has chosen to follow the ISMA Implementation Specification v1 0 for MPEG 4 Part 2 and v2 0 for H 264 This means that RTP is used for media delivery RTSP for media control and SDP for media presentation For efficiency and simplicity data from the codec is not formatted but delivered as an elementary stream in raw format For video surveillance systems the H 264 Baseline Profile is the most suitable due to its low latency and bit rate effectiveness combined with an acceptable complexity The Level used together with the Baseline Profile in Axis products is dependent on the parameter configuration o
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4. 264 standard the most efficient video compression technique available today The reader is presumed to have prior knowledge of Axis platforms Axis platform programming and the H 264 standard Read more about H 264 in the white paper H 264 video compression standard New possibilities within video surveillance published by Axis Communications Firmware 5 xx was developed to take full advantage of the functionality enabled by Axis novel chip technology the ARTPEC 3 and ARTPEC B chips The technical development has been driven by requirements from Axis partners and customers including requests for a more flexible streaming architecture increased performance and improved security The new and improved features required major changes in VAPIX The first part of this document discusses changes in the streaming architecture and in the HTTP and RTSP APIs The second part is a case study showing how Axis implemented support for H 264 in AXIS Camera Station version 3 x The purpose of this guide is to enable application developers to quickly and smoothly integrate Axis new product generation with their own applications For a quick release it suffices to implement changes marked required Recommended and optional changes can wait to a later stage but should eventually also be implemented since it is most likely that obsolete parameters and APIs will not be supported in the future More information about the APIs parameter groups etc can be
5. backwards compatibility for MPEG 4 Part 2 streams in applicable products Axis RTSP implementation complies with the specifications described in RFC 2326 To follow the standard the request line must always contain the complete absolute URL This is necessary in order to support RTSP proxies Relative paths are supported for backwards compatibility but generate a syslog warning Network connections are independent of RTSP sessions such that for example multiple RTSP sessions over the same TCP connection are allowed Remember as of platform 4 4x that an RTSP session must be explicitly opened and closed To keep alive sessions must be controlled by either an RTSP request e g OPTIONS or an RTCP message To prevent the video from keeping transmitting sessions must be closed properly using RTSP The only exception is TCP transport where a live TCP connection is accepted as sign of an active channel This is supported for backwards compatibility wy D gt RE aquired Use the new URL rtsp lt host gt axis media media amp Recommendation All non standard behavior is considered obsolete functionality and will most likely be removed within a few years To accelerate the migration to firmware 5 xx start by implementing the required changes and make a release with those As a second step implement all clients to the full standard 2 2 1 RTSP Authentication With firmware 4 xx authentication was only requested for the
6. first RTSP packet of each TCP connection To allow higher security firmware 5 xx requires authentication of every RTSP packet regardless of the network transport protocol used The only exception is HTTP tunneling over TCP where nothing more than HTTP authentication is required This feature is supported for backwards compatibility and it is strongly recommended to implement full RTSP authentication The backwards compatibility is controlled by the parameter Network RTSP AuthenticateOverHTTP with default value OFF Using the default value authentication is not required at all Applications should be tested with both parameter values on and off To strengthen overall security it is most likely that this feature will be removed or changed in the near future 2 2 2 The media amp interface supports parameters To support multi streaming and permit per stream configuration Axis has extended the media amp interface to support parameters controlling resolution compression use of audio codec etc The new parameters are summarized in Table 1 complete parameter Rev 1 04 Last updated 23 01 2009 8 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide specifications can be found in the VAPIX documentation The interface should be accessed through a new URL rtsp lt host gt axis media media amp where lt host gt is the host name or IP address of the camera or video encoder The syntax for setting
7. in existing products the URL for H 264 was constructed similar to the one used for MPEG 4 Part 2 http lt host gt axis media media amp videocodec h264 NEW http lt host gt mpeg4 media amp OLD The form of the new URL is advantageous as the codec part is separated from the path making updates extensions and other modifications straightforward As in the 4 xx generation the HTTP connection can be authenticated using either Basic or Digest Authentication For better security and compatibility with systems not allowing basic authentication Axis strongly recommends using digest authentication A separate HTTP POST tunnel was used for sending commands to the camera Reference document Apple QuickTime RTSP HTTP streaming Step 2 H 264 specific information in the SDP data The SDP data contains new H 264 specific information Below is an extract from the video media level part of the SDP data red text indicates updated data m video 0 RTP AVP 96 b AS 8000 a framerate 30 0 a control trackID 1 a rtpmap 96 H246 90000 a fmtp 96 packetization mode 1 profile level id 420032 sprop parameter sets ZOIAMuKOFAey aM48gA The encoding name in the rtpmap attribute is changed to H246 This information is needed in order to interpret the information provided in the fmtp attribute The fmtp attribute contains media format specific parameters The packetization mode parameter is used by the client to determine which type of de pac
8. parameter values is similar to the one in the HTTP API for example use rtsp lt host gt axis media media amp videocodec h264 amp audio 0 to select the H 264 codec and disable audio For MPEG 4 Part 2 and H 264 streams Axis has as far as possible used parameters corresponding to the parameters already in use for MJ PEG streams Some parameters are specific to MPEG 4 Part 2 H 264 for example videokeyframeinterval The aspectratio parameter which is the ratio between a pixel s height and width is only used by MJ PEG For the MPEG 4 Part 2 and H 264 formats the aspect ratio information is included in the VOL and VUI headers respectively videocodec h264 The selected video codec mpeg4 in order of priority h264 mpeg4 jpeg jpeg depending on the codecs supported by the product videobitrate 0 integer The rate in kbits s at which video is requested 0 Variable bit rate gt 0 Constant bit rate with the given target bit rate videomaxbitrate 0 integer Maximum bit rate in kbits s for bit rate control videobitratepriority none The priority when rate control is used framerate quality videokeyframeinterval 32 integer Corresponds to the GOV length setting in the web GUI Product and codec dependent audio 1 1 0 Specify whether audio shall be available in the stream for compatibility with applications without audio control Table 1 New parameters in the media amp interface Complet
9. AXIS a COMMUNICATIONS TECHNICAL DOCUMENT Axis Technology Platform Migration Guide Migration from 4 xx to 5 xx Created 29 July 2008 Last updated 23 January 2009 Rev 1 04 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide TABLE OF CONTENTS lntrod cti M aiani rninn naipe inaidai diandani araea 4 mportant Note ssssssssssnsss02uu2225us522uu2uuuunuuununnnnnnnnnnnnnnnnnnnn 4 Document FISCOFY s sssssssssnsnnnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nn 5 1 Support for VAPI X 1 removed e ssssssssss2 25 2 x5 5 2 New Streaming ArchitectUre ssssssss5 6 2 1 Multi streaming chase cateawvercsraiteuconsarvecsesabiuwensauswecesaieeudenuan tees es atewuee 6 2 1 Streaming Protocols ie cies sve sec cescanedacsnesdeeaseetcaces sdesenceusaietacseasdeessean 6 2 1 1 ISMA standard 7 2 1 2 Multicasting 7 2 2 RTSP Server saiiceedancntessniwa teenteonnce danse eussnnscceuewekwadewannccccsnaessnisenesenes 8 2 2 1 RTSP Authentication 8 2 2 2 The media amp interface supports parameters 8 2 3 RTP Packetization and RTP tunneling c sceeeeseeeeeeeeeeeaeeeeeeeeaneees 9 2 4 Audio streaming s ssssssssss5555 55555555555555uu0055uunuunnnnnnnnnnnnnnn nnn 10 2 5 H 264 licensing ssssssssnssnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnna 11 2 6 Summary of media streaming actions sssssssss52255555 2555555 25 11 3 New Tim
10. Moved from Event FileName Moved from Event Suffix Moved from Event Suffix Moved from Event MaxSequenceNumber Moved from Event MaxSequenceNumber Moved from Event Table 5 Event Actions parameter changes 4 1 Video buffering When a triggered event is activated Axis network cameras and video encoders can upload internally stored images from the time periods preceding and following the event using the pre and post trigger buffers New in firmware 5 xx is that post buffering continues if a new trigger is activated during post buffering For example if configured to include 30 seconds post trigger buffering and a new event occurs 20 seconds after the first one post buffering continues for an additional 30 seconds Pre trigger buffering Post trigger buffering 0 30 Time Event 1 Event 2 Figure 2 Video buffering Post buffering starts at Event 1 and is configured to continue for 30 seconds When Event 2 occurs 20 seconds later post buffering continues and ends 60 seconds after Event 1 Keep in mind that the image quality can be temporarily reduced when buffering is activate Buffering has the same effect on the overall device performance as an additional video stream with the same configuration To improve performance and for easier setup pre and post trigger buffers use the same frame rate The buffer command cgi is removed Parameter changes are described in Table 4 and Table 5 5 Security To strengthen overa
11. at jpeg jpeg New Format used for mpeg4 upload recording h264 FrameRate 25 integer New Frame rate per fps second minute hour The same frame fpm rate is used for the pre and post fph buffers fps fpm fph frames per second minute hour PreTriggerSize Replaced by PreTriggerDuration PreTriggerInterval Replaced by PreTriggerDuration PreTriggerUnit Removed No longer needed PreTriggerIntervalUnit Removed No longer needed PreTriggerDuration 0 unsigned New The size of the buffer in integer milliseconds PreTriggerDurationUnit s S New Unit for PreTriggerDuration in m the web interface h PostTriggerSize Replaced by PostTriggerDuration PostTriggerInterval Replaced by PostTriggerDuration PostTriggerUnit Removed No longer needed PostTriggerIntervalUnit Removed No longer needed PostTriggerDuration 0 unsigned New The size of the buffer in integer milliseconds PostTriggerDurationUnit s S New Unit for PostTriggerDuration m in the web interface h BestEffortDuration 0 unsigned Changed from seconds to milliseconds integer BestEffortInterval Removed No longer needed CreateFolder Moved to Actions FileName Moved to Actions Suffix Moved to Actions MaxSequenceNumber Moved to Actions Table 4 General event parameters Rev 1 04 Last updated 23 01 2009 13 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide CreateFolder Moved from Event FileName
12. brOflnputs and Output NbrOfOutputs marked as obsolete 1 04 23 Jan 2009 Addition RTP tunneling over RTSP or HTTP 1 Support for VAPI X 1 removed The HTTP API version 1 VAPIX 1 is not supported in firmware 5 xx products The 3 CGIs getparam cgi setparam cgi audio getparam cgi which were obsolete in version 2 are removed and should be replaced by param cgi To request information about network parameters http lt host gt axis cgi admin getparam cgi Network NEW http lt host gt axis cgi param cgi action list amp group Network To set the default image resolution to 320x240 pixels OLD http lt host gt axis cgi admin setparam cgi Image Resolution 320x240 NEW http lt host gt axis cgi param cgi action update amp Image 10 Resolution 320x240 To request information about audio parameters OLD http lt host gt axis cgi audio getparam cgi NEW http lt host gt axis cgi param cgi action list amp group Audio Rev 1 04 Last updated 23 01 2009 5 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 2 New Streaming Architecture The ARTPEC 3 ARTPEC B chip technology and a new streaming architecture have enabled new functionality in Axis network video products in particular multi streaming and megapixel resolution In addition to several new features Axis partners and customers have requested increased flexibility in t
13. e Format ssssssssnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 11 4 Events Handling sssssssssssnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 12 4 1 Video buffering sssssssssssnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnn 14 5 Sec rity siiivedisicawisansccievadeisuddaddwdsanrsndaserdnannsevacisusenieduucs 14 5 1 Digest Authentication ssssssssssussunuunnuunnnnnnnnnnnnnnnnnnnnnnnnnnnn nnna 15 6 Configurable 1 O Ports sssssssnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 15 7 Error Handling HTTP Status CodeS sssssssssnsnnnnnnnn 17 8 Removed and Obsolete API S ssssssssss5 17 Rev 1 04 Last updated 23 01 2009 2 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 9 Axis H 264 Migration Experiences ss ssssssnnnnnnnnnnnnnnnn LB Step 1 Set up a HTTP GET tunnel 18 Step 2 H 264 specific information in the SDP data 18 Step 3 Support H 264 de packetization 19 Step 4 Identify H 264 frame types 19 Step 5 Enable keep alive 19 10 Axis Development ToolS sssssssnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 2O 11 References asradi aaraa eee ata a aaa aaa ana 2O Rev 1 04 Last updated 23 01 2009 3 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide Introduction This document is intended as a guide for application developers and describes how to migrate to Axis platform 5 xx with emphasis on utilizing the new H
14. e parameter specifications can be found in the VAPI X documentation 2 3 RTP Packetization and RTP tunneling RTP packetization defines how the codec data is split up in RTP packets Axis has implemented packetization for H 264 compliant with RFC 3984 Note that the packetizations for H 264 and MPEG 4 Part 2 are different Required Applications have to implement compatible de packetization See RFC 3984 When RTP is tunneled over RTSP or HTTP the video streaming performance can be considerably improved if the Blocksize header in the RTSP SETUP is set to 64000 instead Rev 1 04 Last updated 23 01 2009 9 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide of the default value 1400 1 With this setting the product will be able to handle more simultaneous video streams and as a bonus the network performance will improve Note that the size of the tunneled RTP packets increases and that the client must be prepared to receive these larger packets Axis has implemented this in AXIS Media Control and strongly recommends the same method for all clients that tunnel RTP over RTSP or HTTP 2 4 Audio streaming In contrast to video stream settings the audio stream settings are global and do not permit per stream configuration with the exception of enabling or disabling audio There is no new audio functionality introduced in firmware 5 xx but a few modifications in the handling of audio streaming a
15. etween daylight saving time and normal time In the 5 xx generation system time is synchronized with UTC GMT time and consequently independent of time zones and daylight saving time In the protocols RTCP RTSP HTTP etc the UTC time appears in either POSIX or EPOCH format Local time is still used in the web interface in text overlays and for scheduled events time controlled events Axis network video products can be queried for local time time 1 The number of free licenses could change Please check with MPEG LA 2 EPOCH is the number of seconds since January 1 1970 not counting leap seconds Rev 1 04 Last updated 23 01 2009 11 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide zones and daylight saving time A new feature in 5 xx is the possibility to include the local time zone and time offset from UTC in the text overlay Time parameter changes are summarized in Table 3 Required The new time format must be considered if time from the video source is used Backwards incompatible root Time UTCOffset root Time DST All except DST Enabled DST daylight saving time root Time NTP Update root Time TimeZone Now in POSIX format Contains information about GMT offsets and daylight saving time Chapter 8 3 The Open Group Base Specifications Issue 6 IEEE Std 1003 1 2004 Edition Z Time zone name or abbreviation Z Time offset fr
16. f the media stream and is chosen automatically to give sufficient bit rate etc 2 1 2 Multicasting Though not recommended in firmware generations preceding 5 xx multicasting could be started from the product setup with media data being transmitted whether or not there were viewing clients It was also possible to fetch client independent SDP data over HTTP Firmware 5 xx removes these deficiencies and improves efficiency by requiring that all multicast sessions should be started properly Data is only transmitted to clients that have explicitly requested access to the video stream Multicasting sessions should be started using RTSP and client dependent SDP data must be explicitly created Clients set up a multicast route using IGMP Rev 1 04 Last updated 23 01 2009 7 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 2 2 RTSP Server To accommodate multi streaming and other new functionality and for security improvements firmware 5 xx introduces a number of changes in the RTSP server The API media amp is accessed through the new URL rtsp lt host gt axis media media amp NEW where lt host gt is the host name or IP address of the camera or video encoder This path should be used for all codecs The old URL rtsp lt host gt mpeg4 lt n gt media amp OLD where lt n gt is the video source number or quad stream only for applicable products is obsolete though still supported for
17. found in the VAPIX documentation Important Note Axis Communications AB provides no guarantee that any of the information given in this document will work for any particular application or that the descriptions will be valid for future platforms firmware or product versions Axis Communications AB can not and will not be held liable for any damage inflicted to any product as a result of the examples or instructions mentioned in this document Axis Communications AB reserves the right to make changes to this document and to platform and product specifications without prior notice Axis Communications AB provides no support for application development of any kind Please bear in mind that the flash chip has a maximum lifespan of about 100 000 writes For this reason writing temporary files to the flash memory should be avoided use the RAM disk mounted on tmp instead Rev 1 04 Last updated 23 01 2009 4 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide Document History Version Date Comment 1 0 29 Jul 2008 Initial version 1 01 6 Nov 2008 Correction Valid values for the Videoformat parameter Addition Multipart streaming in audio transmit cgi not supported 1 02 16 Dec 2008 Correction mpeg 4 to mpeg4 in obsolete paths to media amp Addition New section on Error handling 400 Bad Request 1 03 18 Dec 2008 More removed and obsolete APIs Parameters Input N
18. he IDR frame A H 264 frame on the other hand contains a complete image but does not reset the decoder This means that P frames following an non IDR l frame can reference frames preceding the frame The NAL unit type included in the NAL header was used to recognize IDR and non IDR frames Note that since Axis uses the H 264 Baseline Profile P frames can never refer to frames preceding an frame Reference document ISO IEC 14496 part 10 section 7 4 1 the NAL unit type Step 5 Enable keep alive The final step was to ensure that the RTSP session is kept open so that clients continue to receive media streams With the TCP connection from Step 1 implementing keep alive is not necessary as the established TCP connection already ensures open sessions In order to be able to easily switch transport protocol it still makes sense to implement keep alive As discussed above the RTSP module is completely separated from the underlying communications module 1 IDR Instantaneous Decoding Refresh 2 NAL Network Abstraction Layer Rev 1 04 Last updated 23 01 2009 19 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide Implementing keep alive was straightforward and did not take long The response from the RTSP SETUP command contains a timeout parameter time in seconds For example RTSP 1 0 200 OK Cseq 2 Session 2059134171 timeout 60 Transport RTP AVP TCP unicast inter
19. he architecture in order to smoothly integrate Axis products in their own applications and adapt to different security surveillance and remote monitoring situations Compliance with standard media formats and communications protocols as well as performance and security improvements are other factors driving Axis technology development Disclaimer The new streaming architecture is based on new code and is NOT intended to be bug compatible API and behavior compatibility is maintained wherever possible 2 1 Multi streaming Multi streaming simultaneous streaming of individually configured media streams is the most important new functionality enabled by Axis new chip technology The parameters of each media stream are configured individually permitting different resolutions bit rates and compression levels etc for each stream A typical example is simultaneous streaming of One high quality high bit rate low latency H 264 stream for live video One medium quality medium bit rate high latency H 264 stream for recording One low bandwidth high latency H 264 stream for mobile or WAN One MJPEG stream for legacy players Multi streaming with individually configured media streams gives full flexibility in designing a security surveillance or remote monitoring environment The maximum number of simultaneous media streams varies from 3 for the ARTPEC B chip to 15 20 for ARTPEC 3 Streaming too many high resolution high bit rate stream
20. ketization to use The two comma separated parameters contained in the sprop parameter sets parameter are base 64 encoded One of these parameters is the sequence parameter see ISO IEC Rev 1 04 Last updated 23 01 2009 18 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 14496 part 10 section 7 3 1 and 7 4 1 which contains the picture size and other data required to set up the decoder environment Reference documents RFC 3984 RTP Payload Format for H a Video ISO IEC 14496 part 10 sections 7 3 1 7 3 2 1 7 4 1 and 9 1 Step 3 Support H 264 de packetization RTP packets containing video and audio data are sent in packetized form from the camera or video encoder and must be de packetized before arriving at the decoder After de packetization the original bit stream is recovered and can be processed and sent to the decoder The SDP data from Step 2 specifies packetization mode 1 which should be used to de packetize the RTP packets Note that packetization differs between MPEG 4 Part 2 and H 264 l DEFOT gt rame Figure 3 De packetization of RTP packets Reference documents RFC 3984 sections 5 6 single NAL unit packet and 5 8 fragmented NAL unit packet Step 4 Identify H 264 frame types The H 264 standard defines a new frame type the IDR frame An IDR frame resets the decoder completely so that subsequent P frames cannot reference frames preceding t
21. leaved 52 53 mode PLAY To keep the session alive the RTSP command OPTIONS is sent every 30 seconds timeout 2 The OPTIONS command does not change the state of the camera or video encoder The response from the camera is sent interleaved with the media data in the HTTP GET channel ence document RFC 2326 Real Time Streaming Protocol 10 Axis Development Tools The following tools support the H 264 media format Software development kits SDK e AXIS Media Control SDK v 5 40 e AXIS Media Parser SDK v 3 x e AXIS Camera Station SDK Applications e AXIS Camera Station v 3 x e AXIS Virtual Camera v 3 x 11 References Apple QuickTime RTSP HTTP streaming RFC 3984 RTP Payload Format for H 264 Video http tools ietf org html rfc3984 RFC 2326 Real Time Streaming Protocol http tools ietf org html rfc2326 RFC 2617 HTTP Digest Authentication http tools ietf org html rfc2617 ISO IEC 14496 part 10 sections 7 3 1 7 3 2 1 7 4 1 and 9 1 ISMA standard v1 0 MPEG 4 Part 2 and v2 0 H 264 The Open Group Base Specifications Issue 6 IEEE Std 1003 1 2004 Edition H 264 video compression standard New possibilities within video surveillance White paper from Axis Communications AB http www axis com files whitepaper wp_h264 31669 en 0803 _lo pdf VAPIX documentation including Parameter Specifications Axis Development Guidelines http www axis com techsup cam_servers dev cam_http_api_index php Rev 1
22. ll security provide better resistance against security exploits and prepare for future security updates Axis has made major changes and improvements to the underlying security model Most of these changes are not visible to the user and the required actions are limited to modifying URL paths The old security levels 1 for view 4 for operator 6 for administrator etc are replaced by real access control lists The actual access rights are determined from user identity and group membership instead of being controlled through access to a cgi The default access rights for each user group are the same as in 4 xx Rev 1 04 Last updated 23 01 2009 14 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide In the VAPIX URLs the view operator admin paths are removed For example http lt host gt axis cgi param cgi NEW replaces http lt host gt axis cgi view operator admin param cgi OLD where lt host gt is the host name or IP address of the product For backwards compatibility the old view operator admin paths and scripts still exist and map to the new paths and scripts 5 1 Digest Authentication HTTP Digest Authentication as described in RFC 2617 is used for more secure authentication over both HTTP and RTSP In Axis products Digest Authentication was introduced in firmware 4 xx and remains unchanged in 5 xx Axis strongly recommends implementing digest authentication t
23. o increase overall security and for compatibility with systems and organizations not allowing basic authentication It is most likely that digest authentication will be required by default in the near future 6 Configurable I O Ports Most of Axis network cameras and video encoders have integrated digital input and output ports to connect external equipment such as detectors lights switches and alarm relays The number of ports varies between product models Some products supporting the H 264 video format have configurable I O ports to provide additional flexibility and adaption to demanding security surveillance and remote monitoring situations In these products the port direction can be set to input or output from VAPIX or the web interface To accommodate the configurable ports a new API port egi replaces the old input cgi and output cgi The new API is accessed through http lt host gt axis cgi io port cgi NEW where lt host gt is the host name or IP address of the camera or video encoder The parameters in port egi are summarized in Table 6 The input cgi and output cgi are obsolete but supported for backwards compatibility The new port cgi contains the same functionality as the obsolete input cgi and output cgi To simulate the activation of an input port use virtualinput cgi The Input and Output parameter groups are obsolete and replaced by the new OPort parameter group See Table 7 Required The new API po
24. om UTC Table 3 Time parameter changes 4 Events Handling Most of Axis network cameras and video encoders can be configured to perform certain actions such as uploading images or activate output ports when certain types of events occur Events can be activated by triggers such as video loss motion detection signals from input ports tampering etc or scheduled to occur during pre programmed time periods Support for triggers and actions vary between camera and video encoder models Event configurations are stored as dynamic parameter groups created at runtime which can be set up and configured via HTTP or through the web interface In firmware 5 xx some event parameters have been modified replaced or moved to support the H 264 video format and to provide a simpler more transparent interface The parameter changes are summarized in Table 4 and Table 5 For improved performance and reduced latency the event script functionality is removed and replaced with an application All event handling information is loaded at startup instead of parsing the script every time an event occurs Required Embedded applications using the event script have to be rewritten Backwards incompatible Rev 1 04 Last updated 23 01 2009 12 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide Active Removed VideoForm
25. ormation and complete license terms Up to 100 000 licenses per year can be used for free but an agreement with MPEG LA must always be signed 2 6 Summary of media streaming actions Required Implement H 264 streaming and compatible de packetization Sign agreement with MPEG LA Use the new media amp URL If RTP RTSP HTTP TCP is the only protocol used there are no more required changes If using RTP RTSP TCP or RTP UDP implement RTSP authentication Optional am Teen Support per stream configuration of resolution compression etc Support RTP UDP o Implies extra RTSP authentication for added security and standards compliance o Implement correct session handling for RTP UDP keep alive closing sessions properly Recommended Start with RTP RTSP HTTP TCP if you already support this RTP RTSP TCP and RTP UDP can be left as a future update in many cases Leave per stream configuration to future update without it it works as before o Multi streaming and per stream configuration are major features and should eventually be implemented If RTP is tunneled over RTSP or HTTP set the Blocksize header in the RTSP SETUP request to 64000 3 New Time Format In firmware generations preceding 5 xx internal system time was set to the local time zone so local time was used everywhere in the web interface in user data in protocols etc This caused unwanted gaps and overlays in video data when switching b
26. rig open IoPort I Output Name Output 1 string Replaces Output O Name IOPort I Output Active closed closed Replaces Output O Active open IoPort I Output Button none none Replaces Output O Button pulse actinact IoPort I Output PulseTime 0 integer Replaces Output O PulseTime Input NbrOfInputs Output NbrOfOutputs Table 7 O parameter groups is replaced by a group number starting from 0 1 Product dependent Rev 1 04 Last updated 23 01 2009 16 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 7 Error Handling HTTP Status Codes For CGls that return images or audio the server will return 400 Bad Request if an invalid value for a known URL option is used For example in http myserver axis cgi mjpg video cgi resolution abc abc is not a valid value so 400 Bad Request is returned for firmware 5 xx products For firmware 4 xx products the response is a 200 OK with an error message in the HTTP body 8 Removed and Obsolete APIs Removec axis cgi buffer command cgi MPEG 4 in HTTP API mpeg4 lt camera gt video sdp mpeg4 lt camera gt media sdp axis cgi mpeg4 restart_stream cgi axis cgi mpeg4 _statistics cgi Use axis media media amp VAPIX1 no longer supported axis cgi admin getparam cgi axis cgi admin setparam cgi Replaced by axis cgi param cgi axis cgi audio getparam cgi 1O API axis
27. rt cgi and the new parameter group must be considered in applications using input and or output ports Rev 1 04 Last updated 23 01 2009 15 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide check idl id2 Returns the status 1 or 0 of one or more ports numbered id1 id2 checkactive idl id2 Returns the status active or inactive of one or more ports numbered id1 id2 checkdirection jd1 id2 New functionality Returns the direction input or output of one or more ports numbered id1 id2 monitor id1 id2 Returns a multi stream part of check ports Inputs and outputs must be monitored separately action id lt a gt lt wait gt lt a gt Valid only for output ports lt id gt Port number output1 is default lt a gt action character or active inactive lt wait gt delay in milliseconds Table 6 Parameters in port cgi The checkdirection parameter is new the other parameters are taken from the obsolete input cgi and output cgi IoPort I Configurable yes yes New Check if the port is no configurable Read only and product dependent IoPort I Direction input input New The port direction Read only output for non configurable ports IOPort I Input Name Input 1 string Replaces Input I Name IOPort I Input Trig closed closed Replaces Input I T
28. s at the same time is not recommended since the total encoder performance limits image quality frame rate etc If the encoder becomes overloaded the performance of all streams will be reduced Predicting the maximum number of simultaneous media streams with for example maintained resolution and unreduced frame rate is a non trivial task The performance is hardware dependent and limited due to a range of co working factors including Sensor interface speed the bottleneck between the image sensor and the image processor Sensor specification for example light sensitivity Video scaler performance the scaler is shared by MJ PEG and H 264 and converts the sensor resolution to the requested resolution Codec performance the hardware encoders are separate for MJ PEG and H 264 Main CPU performance External system memory amount and bandwidth For optimal performance Axis recommends to use the same codec resolution compression overlays etc for each simultaneous stream The estimated maximum number of simultaneous high resolution streams for a specific product can be found in the product s datasheet and or User s Manual 2 1 Streaming protocols Axis network video products support multiple combinations of streaming and transport protocols together with the available video and audio formats The options are summarized in Figure 1 where yellow blocks indicate combinations that are new in Rev 1 04 Last updated 23 01 2009 6 gt
29. s summarized in Table 2 The content length parameter which determines the size of the packets in the audio stream used to have a fixed value but is now variable This parameter is used in the HTTP multicast singlepart audio header Audio forwarding is no longer supported and the corresponding parameters are obsolete Transmitting multipart audio streams using audio transmit cgi is no longer supported AAC Multipart is not supported AudioSource A AudioSupport Controls the audio source Requires administrator rights If the audio source is turned off with this parameter no audio will be transmitted even if Audio A Enabled yes Audio NbrOfConfigs Still exists but has no function Audio ForwardOnPost Audio ConnectedClients Audio ConnectedPostClients Audio forwarding Multipart streaming with audio transmit cgi camera Parameter in audio receive cgi Table 2 Audio streaming changes 1 The default value is set to 1400 because some clients have hard coded buffers sizes that cannot handle larger packets Rev 1 04 Last updated 23 01 2009 10 gt gt gt TECHNICAL DOCUMENT Axis Communications Axis Technology Platform Migration Guide 2 5 H 264 licensing H 264 is a licensed technology The patent license portfolio is administrated by the private organization MPEG LA http www mpegla com Required To deploy the H 264 technology in commercial products contact MPEG LA for more inf
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