From dc64f3e6cf00608746324af172f53eb81138b6c6 Mon Sep 17 00:00:00 2001 From: Michael Bunk Date: Fri, 6 Apr 2018 11:17:20 +0200 Subject: [PATCH] docs: fix typos and grammar https://gitlab.freedesktop.org/gstreamer/gst-docs/-/merge_requests/50 Part-of: --- .../markdown/additional/design/conventions.md | 2 +- .../markdown/additional/design/rtp.md | 68 +++++++++---------- .../markdown/additional/design/tracing.md | 8 +-- .../plugin-development/advanced/allocation.md | 6 +- .../plugin-development/advanced/events.md | 16 ++--- .../plugin-development/advanced/interfaces.md | 6 +- .../advanced/media-types.md | 6 +- .../plugin-development/advanced/qos.md | 10 +-- .../plugin-development/advanced/tagging.md | 2 +- .../appendix/checklist-element.md | 2 +- .../element-types/base-classes.md | 6 +- 11 files changed, 66 insertions(+), 66 deletions(-) diff --git a/subprojects/gst-docs/markdown/additional/design/conventions.md b/subprojects/gst-docs/markdown/additional/design/conventions.md index 94b8b077ae..37f7a3bc9a 100644 --- a/subprojects/gst-docs/markdown/additional/design/conventions.md +++ b/subprojects/gst-docs/markdown/additional/design/conventions.md @@ -19,7 +19,7 @@ Within the context of a given object, functions defined in that object’s header and/or source file will have their object-specific prefix stripped. For instance, `gst_element_add_pad()` would be referred to as simply `*add_pad()`. Note that the trailing parentheses should always be -present, but sometimes may not be. A prefixing underscore (*) will +present, but sometimes may not be. A prefixed asterisk (*) will always tell you it’s a function, however, regardless of the presence or absence of the trailing parentheses. diff --git a/subprojects/gst-docs/markdown/additional/design/rtp.md b/subprojects/gst-docs/markdown/additional/design/rtp.md index 5f6daceff0..1dd68c8c43 100644 --- a/subprojects/gst-docs/markdown/additional/design/rtp.md +++ b/subprojects/gst-docs/markdown/additional/design/rtp.md @@ -120,7 +120,7 @@ all have their own distinct ssrc. ## GstRTPRetransmissionRequest Custom upstream event which mainly contains the ssrc and the seqnum of -the packet which is asked to be retransmisted. +the packet which is asked to be retransmitted. On the pipeline receiver side this event is generated by the gstrtpjitterbuffer element. Then it is translated to a NACK to be sent @@ -135,64 +135,64 @@ gstrtpsession element when it receives a NACK from the network. rtprtxsend keeps a history of rtp packets that it has already sent. When it receives the event `GstRTPRetransmissionRequest` from the downstream -gstrtpsession element, it loopkup the requested seqnum in its stored -packets. If the packet is present in its history, it will create a RTX +gstrtpsession element, it looks up the requested seqnum in its stored +packets. If the packet is present in its history, it will create an RTX packet according to RFC 4588. Then this rtx packet is pushed to its src -pad as other packets. +pad like other packets. -rtprtxsend works in SSRC-multiplexed mode, so it has one always sink and +rtprtxsend works in SSRC-multiplexed mode, so it always has one sink and src pad. -### Building retransmission packet fron original packet +### Building retransmission packet from original packet -A rtx packet is mostly the same as an orignal packet, except it has its -own ssrc and its own seqnum. That's why rtprtxsend works in +An rtx packet is mostly the same as an orignal packet, except it has its +own `ssrc` and its own `seqnum`. That's why rtprtxsend works in SSRC-multiplexed mode. It also means that the same session is used. -Another difference between rtx packet and its original is that it +Another difference between an rtx packet and its original is that it inserts the original seqnum (OSN: 2 bytes) at the beginning of the payload. Also rtprtxsend builds rtx packet without padding, to let other elements do that. The last difference is the payload type. For now the -user has to set it through the rtx-payload-type property. Later it will -be automatically retreive this information from SDP. See fmtp field as -specifies in the RPC4588 (a=fmtp:99 apt=98) fmtp is the payload type of -the retransmission stream and apt the payload type of its associated +user has to set it through the `rtx-payload-type` property. Later it will +automatically retreive this information from SDP. See `fmtp` field as +specified in RFC 4588 (a=fmtp:99 apt=98): `fmtp` is the payload type of +the retransmission stream and `apt` the payload type of its associated master stream. ### Retransmission ssrc and seqnum To choose `rtx_ssrc` it randomly selects a number between 0 and 2^32-1 -until it is different than `master_ssrc`. `rtx_seqnum` is randomly -selected between 0 and 2^16-1 +until it is different from `master_ssrc`. `rtx_seqnum` is randomly +selected between 0 and 2^16-1. ### Deeper in the stored buffer history For the history it uses a GSequence with 2^15-1 as its maximum size. Which is resonable as the default value is 100. It contains the packets -in reverse order they have been sent (head:newest, tail:oldest) +in reverse order they have been sent (head:newest, tail:oldest). GSequence allows to add and remove an element in constant time (like a queue). Also GSequence allows to do a binary search when rtprtxsend -lookup in its history. It's important if it receives a lot of requests +does a lookup in its history. It's important if it receives a lot of requests or if the history is large. ### Pending rtx packets When looking up in its history, if seqnum is found then it pushes the -buffer into a GQueue to its tail. Before to send the current master +buffer into a GQueue to its tail. Before sending the current master stream packet, rtprtxsend sends all the buffers which are in this -GQueue. Taking care of converting them to rtx packets. This way, rtx +GQueue, taking care of converting them to rtx packets. This way, rtx packets are sent in the same order they have been requested. -(`g_list_foreach` traverse the queue from head to tail) The `GQueue` is -cleared between sending 2 master stream packets. So for this `GQueue` to -contain more than one element, it means that rtprtxsend receives more +(`g_list_foreach` traverses the queue from head to tail) The `GQueue` is +cleared between sending 2 master stream packets. So when this `GQueue` +contains more than one element, it means that rtprtxsend had received more than one rtx request between sending 2 master packets. ### Collision When handling a `GstRTPCollision` event, if the ssrc is its rtx ssrc then -rtprtxsend clear its history and its pending retransmission queue. Then +rtprtxsend clears its history and its pending retransmission queue. Then it chooses a `rtx_ssrc` until it's different than master ssrc. If the `GstRTPCollision` event does not contain its rtx ssrc, for example its -master ssrc or other, then it just forwards the event to upstream. So +master ssrc or other, then it just forwards the event upstream, so that it can be handled by the rtppayloader. ## Rtprtxreceive element @@ -201,7 +201,7 @@ that it can be handled by the rtppayloader. The same rtprtxreceive instance can receive several master streams and several retransmission streams. So it will try to dynamically associate -a rtx ssrc with its master ssrc. So that it can reconstruct the original +an rtx ssrc with its master ssrc, so that it can reconstruct the original from the proper rtx packet. The algorithm is based on the fact that seqnums of different streams @@ -211,23 +211,23 @@ could also be different. So that they are statistically all different at a given time. If bad luck then the association is delayed to the next rtx request. -The algorithm also needs to know if a given packet is a rtx packet or +The algorithm also needs to know if a given packet is an rtx packet or not. To know this information there is the `rtx-payload-types` property. -For now the user as to configure it but later it will be automatically +For now the user has to configure it but later it will automatically retreive this information from SDP. It needs to know if the current packet is rtx or not in order to know if it can extract the OSN from the payload. Otherwise it would extract the OSN even on master streams which means nothing and so it could do bad things. In theory maybe it could -work but we have this information in SDP so why not using it to avoid +work but we have this information in SDP so why not use it to avoid bad associations. Note that it also means that several master streams can have the same payload type. And also several rtx streams can have the same payload type. So the information from SDP which gives us which rtx payload type -belong to a give master payload type is not enough to do the association +belongs to a given master payload type is not enough to do the association between rtx ssrc and master ssrc. -rtprtxreceive works in SSRC-multiplexed mode, so it has one always sink +rtprtxreceive works in SSRC-multiplexed mode, so it always has one sink and src pad. ### Deeper in the association algorithm @@ -237,20 +237,20 @@ the ssrc and the seqnum from this request. On incoming packets, if the packet has its ssrc already associated then it knows if the ssrc is an rtx ssrc or a master stream ssrc. If this is -a rtx packet then it recontructs the original and pushs the result to -src pad as if it was a master packet. +a rtx packet then it recontructs the original and pushes the result to +the src pad as if it was a master packet. If the ssrc is not yet associated rtprtxreceive checks the payload type. if the packet has its payload type marked as rtx then it will extract the OSN (original seqnum number) and lookup in its stored requests if a -seqnum matchs. If found, then it associates the current ssrc to the +seqnum matches. If found, then it associates the current ssrc to the master ssrc marked in the request. If not found it just drops the packet. Then it removes the request from the stored requests. If there are 2 requests with the same seqnum and different ssrc, then the couple seqnum,ssrc is removed from the stored requests. A stored request actually means that actually the couple seqnum,ssrc is stored. -If it's happens the request is droped but it avoids to do bad +If it happens the request is dropped but it avoids to do bad associations. In this case the association is just delayed to the next request. diff --git a/subprojects/gst-docs/markdown/additional/design/tracing.md b/subprojects/gst-docs/markdown/additional/design/tracing.md index 74e7cf5b9f..34e035c0b3 100644 --- a/subprojects/gst-docs/markdown/additional/design/tracing.md +++ b/subprojects/gst-docs/markdown/additional/design/tracing.md @@ -113,10 +113,10 @@ Hooks (\* already implemented) Tracers are plugin features. They have a simple api: -class init Here the tracers describe the data the will emit. +class init Here the tracers describe the data they will emit. instance init Tracers attach handlers to one or more hooks using -`gst_tracing_register_hook()`. In case the are configurable, they can +`gst_tracing_register_hook()`. In case they are configurable, they can read the options from the *params* property. This is the extra detail from the environment var. @@ -146,7 +146,7 @@ to describe their format: ``` c fmt = gst_tracer_record_new ("thread-rusage.class", // value in the log record (order does not matter) - // *thread-id* is a *key* to related the record to something as indicated + // *thread-id* is a *key* to relate the record to something as indicated // by *scope* substructure "thread-id", GST_TYPE_STRUCTURE, gst_structure_new ("scope", "type", G_TYPE_GTYPE, G_TYPE_GUINT64, @@ -177,7 +177,7 @@ Later tracers can use the `GstTracerRecord` instance to log values efficiently: gst_tracer_record_log (fmt, (guint64) (guintptr) thread_id, avg_cpuload); ``` -Below a few more example for parts of tracer classes: +Below a few more examples for parts of tracer classes: An optional value. Since the PTS can be GST_CLOCK_TIME_NONE and that is (-1), we don't want to log this. diff --git a/subprojects/gst-docs/markdown/plugin-development/advanced/allocation.md b/subprojects/gst-docs/markdown/plugin-development/advanced/allocation.md index bdff786abc..d2308b02c1 100644 --- a/subprojects/gst-docs/markdown/plugin-development/advanced/allocation.md +++ b/subprojects/gst-docs/markdown/plugin-development/advanced/allocation.md @@ -18,9 +18,9 @@ This chapter talks about the memory-management features available to GStreamer plugins. We will first talk about the lowlevel `GstMemory` object that manages access to a piece of memory and then continue with one of it's main users, the `GstBuffer`, which is used to exchange data -between plugins and with the application. We will also discuss the `GstMeta`. -This object can be placed on buffers to provide extra info about it and -its memory. We will also discuss the `GstBufferPool`, which allows to +between elements and with the application. We will also discuss the `GstMeta`. +This object can be placed on buffers to provide extra info about them and +their memory. We will also discuss the `GstBufferPool`, which allows to more-efficiently manage buffers of the same size. To conclude this chapter we will take a look at the `GST_QUERY_ALLOCATION` diff --git a/subprojects/gst-docs/markdown/plugin-development/advanced/events.md b/subprojects/gst-docs/markdown/plugin-development/advanced/events.md index 12f7f330ea..331f26fea2 100644 --- a/subprojects/gst-docs/markdown/plugin-development/advanced/events.md +++ b/subprojects/gst-docs/markdown/plugin-development/advanced/events.md @@ -71,7 +71,7 @@ If your element is exclusively loop-based, you may or may not want a sink event function (since the element is driving the pipeline it will know the length of the stream in advance or be notified by the flow return value of `gst_pad_pull_range()`. In some cases even loop-based -element may receive events from upstream though (for example audio +elements may receive events from upstream though (for example audio decoders with an id3demux or apedemux element in front of them, or demuxers that are being fed input from sources that send additional information about the stream in custom events, as DVD sources do). @@ -80,7 +80,7 @@ information about the stream in custom events, as DVD sources do). Upstream events are generated by an element somewhere downstream in the pipeline (example: a video sink may generate navigation events that -informs upstream elements about the current position of the mouse +inform upstream elements about the current position of the mouse pointer). This may also happen indirectly on request of the application, for example when the application executes a seek on a pipeline this seek request will be passed on to a sink element which will then in turn @@ -90,13 +90,13 @@ The most common upstream events are seek events, Quality-of-Service (QoS) and reconfigure events. An upstream event can be sent using the `gst_pad_send_event` function. -This function simply call the default event handler of that pad. The +This function simply calls the default event handler of that pad. The default event handler of pads is `gst_pad_event_default`, and it basically sends the event to the peer of the internally linked pad. So upstream events always arrive on the src pad of your element and are handled by the default event handler except if you override that handler to handle it yourself. There are some specific cases where you have to -do that : +do that: - If you have multiple sink pads in your element. In that case you will have to decide which one of the sink pads you will send the @@ -109,7 +109,7 @@ do that : The processing you will do in that event handler does not really matter but there are important rules you have to absolutely respect because one broken element event handler is breaking the whole pipeline event -handling. Here they are : +handling. Here they are: - Always handle events you won't handle using the default `gst_pad_event_default` method. This method will depending on the @@ -118,7 +118,7 @@ handling. Here they are : - If you are generating some new event based on the one you received don't forget to gst\_event\_unref the event you received. - - Event handler function are supposed to return TRUE or FALSE + - Event handler functions are supposed to return TRUE or FALSE indicating if the event has been handled or not. Never simply return TRUE/FALSE in that handler except if you really know that you have handled that event. @@ -130,7 +130,7 @@ handling. Here they are : ## All Events Together In this chapter follows a list of all defined events that are currently -being used, plus how they should be used/interpreted. You can check the +being used, plus how they should be used/interpreted. You can check what type a certain event is using the GST\_EVENT\_TYPE macro (or if you need a string for debugging purposes you can use GST\_EVENT\_TYPE\_NAME). @@ -197,7 +197,7 @@ should be sent on. The last is true for demuxers, which generally have a byte-to-time conversion concept. Their input is usually byte-based, so the incoming event will have an offset in byte units (`GST_FORMAT_BYTES`), too. Elements downstream, however, expect segment -events in time units, so that it can be used to synchronize against the +events in time units, so that they can be used to synchronize against the pipeline clock. Therefore, demuxers and similar elements should not forward the event, but parse it, free it and send a segment event (in time units, `GST_FORMAT_TIME`) further downstream. diff --git a/subprojects/gst-docs/markdown/plugin-development/advanced/interfaces.md b/subprojects/gst-docs/markdown/plugin-development/advanced/interfaces.md index 621f96a390..941bc53236 100644 --- a/subprojects/gst-docs/markdown/plugin-development/advanced/interfaces.md +++ b/subprojects/gst-docs/markdown/plugin-development/advanced/interfaces.md @@ -16,11 +16,11 @@ a spin-button widget, whereas others would be better represented by a slider widget. Such things are not possible because the UI has no actual meaning in the application. A UI widget that represents a bitrate property is the same as a UI widget that represents the size of a video, -as long as both are of the same `GParamSpec` type. Another problem, is +as long as both are of the same `GParamSpec` type. Another problem is that things like parameter grouping, function grouping, or parameter coupling are not really possible. -The second problem with parameters are that they are not dynamic. In +The second problem with parameters is that they are not dynamic. In many cases, the allowed values for a property are not fixed, but depend on things that can only be detected at runtime. The names of inputs for a TV card in a video4linux source element, for example, can only be @@ -125,7 +125,7 @@ WRITEME ## Video Overlay Interface -The `GstVideoOverlay` interface is used for 2 main purposes : +The `GstVideoOverlay` interface is used for 2 main purposes: - To get a grab on the Window where the video sink element is going to render. This is achieved by either being informed about the Window diff --git a/subprojects/gst-docs/markdown/plugin-development/advanced/media-types.md b/subprojects/gst-docs/markdown/plugin-development/advanced/media-types.md index 20606a8e30..bba42c3f9c 100644 --- a/subprojects/gst-docs/markdown/plugin-development/advanced/media-types.md +++ b/subprojects/gst-docs/markdown/plugin-development/advanced/media-types.md @@ -7,7 +7,7 @@ title: Media Types and Properties There is a very large set of possible media types that may be used to pass data between elements. Indeed, each new element that is defined may use a new data format (though unless at least one other element recognises -that format, it will be most likely be useless since nothing will be +that format, it will be useless since nothing will be able to link with it). In order for media types to be useful, and for systems like autopluggers to @@ -25,7 +25,7 @@ For now, the policy is simple: - If creating a new media type, discuss it first with the other GStreamer developers, on at least one of: IRC, mailing lists. - - Try to ensure that the name for a new format is as unlikely to + - Try to ensure that the name for a new format does not conflict with anything else created already, and is not a more generalised name than it should be. For example: "audio/compressed" would be too generalised a name to represent audio data compressed @@ -149,7 +149,7 @@ samplerate of the contained audio stream in the header. MPEG system streams don't. This means that an AVI stream demuxer would provide samplerate as a property for MPEG audio streams, whereas an MPEG demuxer would not. A decoder needing this data would require a stream parser in -between two extract this from the header or calculate it from the +between to extract this from the header or calculate it from the stream. ### Table of Audio Types diff --git a/subprojects/gst-docs/markdown/plugin-development/advanced/qos.md b/subprojects/gst-docs/markdown/plugin-development/advanced/qos.md index 0e524e0004..02144d9a84 100644 --- a/subprojects/gst-docs/markdown/plugin-development/advanced/qos.md +++ b/subprojects/gst-docs/markdown/plugin-development/advanced/qos.md @@ -67,7 +67,7 @@ the sink. An element will have to install an event function on its source pads in order to receive QOS events. Usually, the element will need to store the -value of the QOS event and use them in the data processing function. The +value of the QOS event and use it in the data processing function. The element will need to use a lock to protect these QoS values as shown in the example below. Also make sure to pass the QoS event upstream. @@ -111,7 +111,7 @@ timestamp + jitter is also going to be late. We can thus drop all buffers with a timestamp less than timestamp + jitter. If the buffer duration is known, a better estimation for the next likely -timestamp as: timestamp + 2 \* jitter + duration. +timestamp to arrive in time is: timestamp + 2 \* jitter + duration. A possible algorithm typically looks like this: @@ -205,7 +205,7 @@ conditions: - The element dropped a buffer because of QoS reasons. - - An element changes its processing strategy because of QoS reasons - (quality). This could include a decoder that decides to drop every B + - An element changed its processing strategy because of QoS reasons + (quality). This could include a decoder that decided to drop every B frame to increase its processing speed or an effect element - switching to a lower quality algorithm. + that switched to a lower quality algorithm. diff --git a/subprojects/gst-docs/markdown/plugin-development/advanced/tagging.md b/subprojects/gst-docs/markdown/plugin-development/advanced/tagging.md index 6dfa4ae3b4..c1c31ca3ed 100644 --- a/subprojects/gst-docs/markdown/plugin-development/advanced/tagging.md +++ b/subprojects/gst-docs/markdown/plugin-development/advanced/tagging.md @@ -220,7 +220,7 @@ gst_my_filter_task_func (GstElement *element) ``` -Note that normally, elements would not read the full stream before +Note that normally elements would not read the full stream before processing tags. Rather, they would read from each sinkpad until they've received data (since tags usually come in before the first data buffer) and process that. diff --git a/subprojects/gst-docs/markdown/plugin-development/appendix/checklist-element.md b/subprojects/gst-docs/markdown/plugin-development/appendix/checklist-element.md index e6504a530e..89111e1b03 100644 --- a/subprojects/gst-docs/markdown/plugin-development/appendix/checklist-element.md +++ b/subprojects/gst-docs/markdown/plugin-development/appendix/checklist-element.md @@ -122,5 +122,5 @@ we will try to explain why those requirements are set. with unseekable input streams (e.g. network sources) as well. - Sources and sinks should be prepared to be assigned another clock - then the one they expose themselves. Always use the provided clock + than the one they expose themselves. Always use the provided clock for synchronization, else you'll get A/V sync issues. diff --git a/subprojects/gst-docs/markdown/plugin-development/element-types/base-classes.md b/subprojects/gst-docs/markdown/plugin-development/element-types/base-classes.md index 652d16021c..f3e4a2ab9b 100644 --- a/subprojects/gst-docs/markdown/plugin-development/element-types/base-classes.md +++ b/subprojects/gst-docs/markdown/plugin-development/element-types/base-classes.md @@ -5,7 +5,7 @@ title: Pre-made base classes # Pre-made base classes So far, we've been looking at low-level concepts of creating any type of -GStreamer element. Now, let's assume that all you want is to create an +GStreamer element. Now, let's assume that all you want is to create a simple audiosink that works exactly the same as, say, “esdsink”, or a filter that simply normalizes audio volume. Such elements are very general in concept and since they do nothing special, they should be @@ -31,7 +31,7 @@ in many elements. Therefore, sink elements can derive from the functions automatically. The derived class only needs to implement a bunch of virtual functions and will work automatically. -The base class implement much of the synchronization logic that a sink +The base class implements much of the synchronization logic that a sink has to perform. The `GstBaseSink` base-class specifies some limitations on elements, @@ -65,7 +65,7 @@ The advantages of deriving from `GstBaseSink` are numerous: not need to know anything about the technical implementation requirements of preroll. The base-class does all the hard work. - Less code to write in the derived class, shared code (and thus + - Less code to write in the derived class, shared code (and thus shared bugfixes). There are also specialized base classes for audio and video, let's look