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gstreamer/ext/avtp/meson.build

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avtp: AVTP plugin bootstrap code This patch introduces the bootstrap code from the AVTP plugin (plugin definition and init) as well as the build system files. Upcoming patches will introduce payloaders, source and sink elements provided by the AVTP plugin. These elements can be utilized by a GStreamer pipeline to implement TSN audio/video applications. Regarding the plugin build system files, both autotools and meson files are introduced. The AVTP plugin is landed in ext/ since it has an external dependency on libavtp, an opensource AVTP packetization library. For further information about libavtp check [1]. [1] https://github.com/AVnu/libavtp
2019-01-14 18:18:42 +00:00
avtp_sources = [
'gstavtp.c',
avtp: Introduce AAF depayloader element This patch introduces the AAF depayloader element, the counterpart from the AAF payloader. As expected, this element inputs AVTPDUs and outputs audio raw data and supports AAF PCM encapsulation only. The AAF depayloader srcpad produces a fixed format that is encoded within the AVTPDU. Once the first AVTPDU is received by the element, the audio features e.g. sample format, rate, number of channels, are decoded and the srcpad caps are set accordingly. Also, at this point, the element pushes a SEGMENT event downstream defining the segment according to the AVTP presentation time. All AVTP depayloaders will share some common code. For that reason, this patch introduces the GstAvtpBaseDepayload abstract class that implements common depayloader functionalities. AAF-specific functionalities are implemented in the derived class GstAvtpAafDepay.
2019-01-24 00:20:27 +00:00
'gstavtpaafdepay.c',
avtp: Introduce AAF payloader element This patch introduces the AVTP Audio Format (AAF) payloader element from the AVTP plugin. The element inputs audio raw data and outputs AVTP packets (aka AVTPDUs), implementing a typical protocol payloader element from GStreamer. AAF is one of the available formats to transport audio data in an AVTP system. AAF is specified in IEEE 1722-2016 section 7 and provides two encapsulation mode: PCM and AES3. This patch implements PCM encapsulation mode only. The AAF payloader working mechanism consists of building the AAF header, prepending it to the GstBuffer received on the sink pad, and pushing the buffer downstream. Payloader parameters such as stream ID, maximum transit time, time uncertainty, and timestamping mode are passed via element properties. AAF doesn't support all possible sample format and sampling rate values so the sink pad caps template from the payloader is a subset of audio/x-raw. Additionally, this patch implements only "normal" timestamping mode from AAF. "Sparse" mode should be implemented in future. Upcoming patches will introduce other AVTP payloader elements that will have some common code. For that reason, this patch introduces the GstAvtpBasePayload abstract class that implements common payloader functionalities, and the GstAvtpAafPay class that extends the GstAvtpBasePayload class, implementing AAF-specific functionalities. The AAF payloader element is most likely to be used with the AVTP sink element (to be introduced by a later patch) but it could also be used with UDP sink element to implement AVTP over UDP as described in IEEE 1722-2016 Annex J. This element was inspired by RTP payloader elements.
2019-01-17 01:16:59 +00:00
'gstavtpaafpay.c',
avtp: Introduce AVTP CVF depayloader element This patch introduces the AVTP Compressed Video Format (CVF) depayloader specified in IEEE 1722-2016 section 8. Currently, this depayloader only supports H.264 encapsulation described in section 8.5. Is also worth noting that only single NAL units are handled: aggregated and fragmented payloads are not handled. As stated in AVTP CVF payloader patch, AVTP timestamp is used to define outgoing buffer DTS, while the H264_TIMESTAMP defines outgoing buffer PTS. When an AVTP packet is received, the extracted H.264 NAL unit is added to a "stash" (the out_buffer) of H.264 NAL units. This "stash" is pushed downstream as single buffer (with NAL units aggregated according to format used on GStreamer, based on ISO/IEC 14496-15) as soon as we get the AVTP packet with M bit set. This patch groups NAL units using a fixed NAL size lenght, sent downstream on the `codec_data` capability. The "stash" of NAL units can be prematurely sent downstream if a discontinuity (a missing SEQNUM) happens. This patch reuses the infra provided by gstavtpbasedepayload.c.
2019-03-12 22:46:16 +00:00
'gstavtpcvfdepay.c',
avtp: Introduce AVTP CVF payloader element This patch introduces the AVTP Compressed Video Format (CVF) payloader specified in IEEE 1722-2016 section 8. Currently, this payload only supports H.264 encapsulation described in section 8.5. Is also worth noting that only single NAL units are encapsulated: no aggregation or fragmentation is performed by the payloader. An interesting characteristic of CVF H.264 spec is that it defines an H264_TIMESTAMP, in addition to the AVTP timestamp. The later is translated to the GST_BUFFER_DTS while the former is translated to the GST_BUFFER_PTS. From AVTP CVF H.264 spec, it is clear that the AVTP timestamp is related to the decoding order, while the H264_TIMESTAMP is an ancillary information to the H.264 decoder. Upon receiving a buffer containing a group of NAL units, the avtpcvfpay element will extract each NAL unit and payload them into individual AVTP packets. The last AVTP packet generated for a group of NAL units will have the M bit set, so the depayloader is able to properly regroup them. The exact format of the buffer of NAL units is described on the 'codec_data' capability, which is parsed by the avtpcvfpay, in the same way done in rtph264pay. This patch reuses the infra provided by gstavtpbasepayload.c.
2019-02-28 23:49:02 +00:00
'gstavtpcvfpay.c',
avtp: Introduce AAF depayloader element This patch introduces the AAF depayloader element, the counterpart from the AAF payloader. As expected, this element inputs AVTPDUs and outputs audio raw data and supports AAF PCM encapsulation only. The AAF depayloader srcpad produces a fixed format that is encoded within the AVTPDU. Once the first AVTPDU is received by the element, the audio features e.g. sample format, rate, number of channels, are decoded and the srcpad caps are set accordingly. Also, at this point, the element pushes a SEGMENT event downstream defining the segment according to the AVTP presentation time. All AVTP depayloaders will share some common code. For that reason, this patch introduces the GstAvtpBaseDepayload abstract class that implements common depayloader functionalities. AAF-specific functionalities are implemented in the derived class GstAvtpAafDepay.
2019-01-24 00:20:27 +00:00
'gstavtpbasedepayload.c',
avtp: Introduce AAF payloader element This patch introduces the AVTP Audio Format (AAF) payloader element from the AVTP plugin. The element inputs audio raw data and outputs AVTP packets (aka AVTPDUs), implementing a typical protocol payloader element from GStreamer. AAF is one of the available formats to transport audio data in an AVTP system. AAF is specified in IEEE 1722-2016 section 7 and provides two encapsulation mode: PCM and AES3. This patch implements PCM encapsulation mode only. The AAF payloader working mechanism consists of building the AAF header, prepending it to the GstBuffer received on the sink pad, and pushing the buffer downstream. Payloader parameters such as stream ID, maximum transit time, time uncertainty, and timestamping mode are passed via element properties. AAF doesn't support all possible sample format and sampling rate values so the sink pad caps template from the payloader is a subset of audio/x-raw. Additionally, this patch implements only "normal" timestamping mode from AAF. "Sparse" mode should be implemented in future. Upcoming patches will introduce other AVTP payloader elements that will have some common code. For that reason, this patch introduces the GstAvtpBasePayload abstract class that implements common payloader functionalities, and the GstAvtpAafPay class that extends the GstAvtpBasePayload class, implementing AAF-specific functionalities. The AAF payloader element is most likely to be used with the AVTP sink element (to be introduced by a later patch) but it could also be used with UDP sink element to implement AVTP over UDP as described in IEEE 1722-2016 Annex J. This element was inspired by RTP payloader elements.
2019-01-17 01:16:59 +00:00
'gstavtpbasepayload.c',
avtp: Introduce AVTP sink element This patch introduces the avtpsink elements which implements a typical network sink. Implementation is pretty straightforward since the burden is implemented by GstBaseSink class. The avtpsink element defines three new properties: 1) network interface from where AVTPDU should be transmitted, 2) destination MAC address (usually a multicast address), and 3) socket priority (SO_PRIORITY). Socket setup and teardown are done in start/stop virtual methods while AVTPDU transmission is carried out by render(). AVTPDUs are encapsulated into Ethernet frames and transmitted to the network via AF_PACKET socket domain. Linux requires CAP_NET_RAW capability in order to open an AF_PACKET socket so the application that utilize this element must have it. For further info about AF_PACKET socket domain see packet(7). Finally, AVTPDUs are expected to be transmitted at specific times - according to the GstBuffer presentation timestamp - so the 'sync' property from GstBaseSink is set to TRUE by default.
2019-01-23 18:56:10 +00:00
'gstavtpsink.c',
avtp: Introduce AVTP source element This patch introduces the avtpsrc element which implements a typical network source. The avtpsrc element receives AVTPDUs encapsulated into Ethernet frames and push them downstream in the GStreamer pipeline. Implementation if pretty straightforward since the burden is implemented by GstPushSrc class. Likewise the avtpsink element, applications that utilize this element must have CAP_NET_RAW capability since it is required by Linux to open sockets from AF_PACKET domain.
2019-01-23 23:17:48 +00:00
'gstavtpsrc.c',
avtp: Introduce the CRF Sync Element This commit introduces the AVTP Clock Reference Format (CRF) Synchronizer element. This element implements the AVTP CRF Listener as described in IEEE 1722-2016 Section 10. CRF is useful in synchronizing events within different systems by distributing a common clock. This is useful in a scenario where there are multiple talkers who are sending data to a single listener which is processing that data. E.g. CCTV cameras on a network sending AVTP video streams to a base station to display on the same screen. It is assumed that all the systems are already time-synchronized with each other. So, the AVTP Talker essentially adjusts the AVTP Presentation Time so it's phase-locked with the reference clock provided by the CRF stream. There are 2 different roles of systems which participate in CRF data exchange. A system can either be a CRF Talker, which samples it's own clock and generates a stream of timestamps to transmit over the network, or a CRF Listener, the system which receives the generated timestamps and recovers the media clock from the timestamps. It then adjusts it's own clock to align with recovered media clock. The timestamps generated by the talker may not be continuous and the listener might have to interpolate some timestamps to recover the media clock. The number of timestamps to interpolate is mentioned in the CRF stream AVTPDU (Refer IEEE 1722-2016 Section 10.4 for AVTPDU structure). Only CRF Listener has been implemented in this commit. The CRF Sync element will create a separate thread to listen for the CRF stream. This thread will calculate and store the average period of the recovered media clock. The pipeline thread will use this stored period along with the first timestamp of the latest CRF AVTPDU received to calculate adjustment for timestamps in the audio/video streams. In case of CRF AVTPDUs with single timestamp, two consecutive CRF AVTPDUs will be used to figure out the average period of the recovered media clock. In case of H264 streams, both AVTP timestamp and H264 timestamp will be adjusted. In the future commits, another "CRF Checker" element will be introduced which will validate the timestamps on the AVTP Listener side. Which is why a lot of code has been implemented as part of the gstcrfbase class.
2020-02-06 00:17:39 +00:00
'gstavtpcrfutil.c',
'gstavtpcrfbase.c',
'gstavtpcrfsync.c',
avtp: Introduce the CRF Check element This commit introduces the AVTP Clock Reference Format (CRF) Checker element. This element re-uses the GstAvtpCrfBase class introduced along with the CRF Synchronizer element. This element will typically be used along with the avtpsrc element to ensure that the AVTP timestamp (and H264 timestamp in case of CVF-H264 packets) is "aligned" with the incoming CRF stream. Here, "aligned" means that the timestamp value should be within 25% of the period of the media clock recovered from the CRF stream. The user can also set an option (drop-invalid) in order to drop any packet whose timestamp is not within the thresholds of the incoming CRF stream.
2019-10-14 20:55:57 +00:00
'gstavtpcrfcheck.c',
avtp: AVTP plugin bootstrap code This patch introduces the bootstrap code from the AVTP plugin (plugin definition and init) as well as the build system files. Upcoming patches will introduce payloaders, source and sink elements provided by the AVTP plugin. These elements can be utilized by a GStreamer pipeline to implement TSN audio/video applications. Regarding the plugin build system files, both autotools and meson files are introduced. The AVTP plugin is landed in ext/ since it has an external dependency on libavtp, an opensource AVTP packetization library. For further information about libavtp check [1]. [1] https://github.com/AVnu/libavtp
2019-01-14 18:18:42 +00:00
]
avtp_dep = dependency('avtp', required: get_option('avtp'))
avtpsink: Implement synchronization mechanism The avtpsink element is expected to transmit AVTPDUs at specific times, according to GstBuffer timestamps. Currently, the transmission time is controlled in software via the rendering synchronization mechanism provided by GstBaseSink class. However, that mechanism may not cope with some AVB use-cases such as Class A streams, where AVTPDUs are expected to be transmitted at every 125 us. Thus, this patch introduces avtpsink own mechanism which leverages the socket transmission scheduling infrastructure introduced in Linux kernel 4.19. When supported by the NIC, the transmission scheduling is offloaded to the hardware, improving transmission time accuracy considerably. To illustrate that, a before-after experiment was carried out. The experimental setup consisted in 2 PCs with Intel i210 card connected back-to-back running an up-to-date Archlinux with kernel 5.3.1. In one host gst-launch-1.0 was used to generate a 2-minute Class A stream while the other host captured the packets. The metric under evaluation is the transmission interval and it is measured by checking the 'time_delta' information from ethernet frames captured at the receiving side. The table below shows the outcome for a 48 kHz, 16-bit sample, stereo audio stream. The unit is nanoseconds. | Mean | Stdev | Min | Max | Range | -------+--------+---------+---------+---------+---------+ Before | 125000 │ 2401 │ 110056 │ 288432 │ 178376 | After | 125000 │ 18 │ 124943 │ 125055 │ 112 | Before this patch, the transmission interval mean is equal to the optimal value (Class A stream -> 125 us interval), and it is kept the same after the patch. The dispersion measurements, however, had improved considerably, meaning the system is now consistently transmitting AVTPDUs at the correct time. Finally, the socket transmission scheduling infrastructure requires the system clock to be synchronized with PTP clock so this patches modifies the AVTP plugin documentation to cover how to achieve that.
2019-10-04 18:39:10 +00:00
if avtp_dep.found() and cc.has_type('struct sock_txtime', prefix : '#include <linux/net_tstamp.h>')
avtp: AVTP plugin bootstrap code This patch introduces the bootstrap code from the AVTP plugin (plugin definition and init) as well as the build system files. Upcoming patches will introduce payloaders, source and sink elements provided by the AVTP plugin. These elements can be utilized by a GStreamer pipeline to implement TSN audio/video applications. Regarding the plugin build system files, both autotools and meson files are introduced. The AVTP plugin is landed in ext/ since it has an external dependency on libavtp, an opensource AVTP packetization library. For further information about libavtp check [1]. [1] https://github.com/AVnu/libavtp
2019-01-14 18:18:42 +00:00
gstavtp = library('gstavtp',
avtp_sources,
c_args : gst_plugins_bad_args,
include_directories : [configinc],
avtp: Introduce the CRF Sync Element This commit introduces the AVTP Clock Reference Format (CRF) Synchronizer element. This element implements the AVTP CRF Listener as described in IEEE 1722-2016 Section 10. CRF is useful in synchronizing events within different systems by distributing a common clock. This is useful in a scenario where there are multiple talkers who are sending data to a single listener which is processing that data. E.g. CCTV cameras on a network sending AVTP video streams to a base station to display on the same screen. It is assumed that all the systems are already time-synchronized with each other. So, the AVTP Talker essentially adjusts the AVTP Presentation Time so it's phase-locked with the reference clock provided by the CRF stream. There are 2 different roles of systems which participate in CRF data exchange. A system can either be a CRF Talker, which samples it's own clock and generates a stream of timestamps to transmit over the network, or a CRF Listener, the system which receives the generated timestamps and recovers the media clock from the timestamps. It then adjusts it's own clock to align with recovered media clock. The timestamps generated by the talker may not be continuous and the listener might have to interpolate some timestamps to recover the media clock. The number of timestamps to interpolate is mentioned in the CRF stream AVTPDU (Refer IEEE 1722-2016 Section 10.4 for AVTPDU structure). Only CRF Listener has been implemented in this commit. The CRF Sync element will create a separate thread to listen for the CRF stream. This thread will calculate and store the average period of the recovered media clock. The pipeline thread will use this stored period along with the first timestamp of the latest CRF AVTPDU received to calculate adjustment for timestamps in the audio/video streams. In case of CRF AVTPDUs with single timestamp, two consecutive CRF AVTPDUs will be used to figure out the average period of the recovered media clock. In case of H264 streams, both AVTP timestamp and H264 timestamp will be adjusted. In the future commits, another "CRF Checker" element will be introduced which will validate the timestamps on the AVTP Listener side. Which is why a lot of code has been implemented as part of the gstcrfbase class.
2020-02-06 00:17:39 +00:00
dependencies : [gstaudio_dep, gstvideo_dep, avtp_dep, libm],
avtp: AVTP plugin bootstrap code This patch introduces the bootstrap code from the AVTP plugin (plugin definition and init) as well as the build system files. Upcoming patches will introduce payloaders, source and sink elements provided by the AVTP plugin. These elements can be utilized by a GStreamer pipeline to implement TSN audio/video applications. Regarding the plugin build system files, both autotools and meson files are introduced. The AVTP plugin is landed in ext/ since it has an external dependency on libavtp, an opensource AVTP packetization library. For further information about libavtp check [1]. [1] https://github.com/AVnu/libavtp
2019-01-14 18:18:42 +00:00
install : true,
install_dir : plugins_install_dir,
)
pkgconfig.generate(gstavtp, install_dir : plugins_pkgconfig_install_dir)
docs: Add AVTP elements documentation
2019-04-17 00:32:46 +00:00
plugins += [gstavtp]
avtp: AVTP plugin bootstrap code This patch introduces the bootstrap code from the AVTP plugin (plugin definition and init) as well as the build system files. Upcoming patches will introduce payloaders, source and sink elements provided by the AVTP plugin. These elements can be utilized by a GStreamer pipeline to implement TSN audio/video applications. Regarding the plugin build system files, both autotools and meson files are introduced. The AVTP plugin is landed in ext/ since it has an external dependency on libavtp, an opensource AVTP packetization library. For further information about libavtp check [1]. [1] https://github.com/AVnu/libavtp
2019-01-14 18:18:42 +00:00
endif
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