nginx-pckg-module

Nginx Packager Module

Stateless live media packager.

Required dependencies: nginx-common

Optional dependencies:

• openssl - required for media encryption / DRM
• libavcodec - required for video frame capture
• libswscale - required for scaling captured video frames

Features

• Input protocol: KSMP

• Output

  • protocols: HLS / LLHLS, DASH
  • containers: MPEG-TS, fMP4, WebVTT

• Codecs

  • Video: h264 / AVC, h265 / HEVC
  • Audio: AAC, MP3, AC3, E-AC3, OPUS
  • Subtitle: WebVTT, TTML

• Adaptive bitrate

• Alternative audio

• Media encryption / DRM

• Video frame capture

Sample Configuration

http {

    # Capture channel / timeline ids from URI
    map $uri $channel_id {
        ~/ch/(?P<result>[^/]+) $result;
        default '';
    }

    map $uri $timeline_id {
        ~/tl/(?P<result>[^/]+) $result;
        default 'main';
    }

    server {
        listen 80;
        server_name _;

        # CORS headers
        add_header Access-Control-Allow-Headers 'Origin,Range,Accept-Encoding,Referer,Cache-Control';
        add_header Access-Control-Expose-Headers 'Server,Content-Length,Content-Range,Date,Age';
        add_header Access-Control-Allow-Methods 'GET,HEAD,OPTIONS';
        add_header Access-Control-Allow-Origin '*';

        # Compress manifests
        gzip on;
        gzip_types application/vnd.apple.mpegurl video/f4m application/dash+xml text/xml text/vtt;
        gzip_proxied any;

        # Shared packager directives
        pckg_uri /ksmp_proxy/;
        pckg_channel_id $channel_id;
        pckg_timeline_id $timeline_id;
        pckg_m3u8_low_latency on;

        # Clear HLS/DASH
        location /clear/ {
            pckg;
        }

        # Clear key HLS AES-128
        location /aes128/ {
            pckg;

            pckg_enc_scheme aes-128;
            pckg_enc_key_seed 'Secret123$channel_id';
        }

        # Clear key HLS SAMPLE-AES
        location /cbcs/ {
            pckg;

            pckg_enc_scheme cbcs;
            pckg_enc_key_seed 'Secret123$channel_id';
        }

        # DRM HLS/DASH cenc scheme
        location /drm-cenc/ {
            pckg;

            pckg_enc_scheme cenc;
            pckg_enc_json $pckg_var_drm_cenc_json;

            pckg_m3u8_container fmp4;
            pckg_m3u8_mux_segments off;
            pckg_m3u8_enc_output_iv off;
            pckg_m3u8_enc_key_format 'urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed';
            pckg_m3u8_enc_key_format_versions '1';
        }

        # DRM FairPlay HLS
        location /drm-fps/ {
            pckg;

            pckg_enc_scheme cbcs;
            pckg_enc_json $pckg_var_drm_cbcs_json;

            pckg_m3u8_enc_output_iv off;
            pckg_m3u8_enc_key_uri 'skd://channel-$channel_id';
            pckg_m3u8_enc_key_format 'com.apple.streamingkeydelivery';
            pckg_m3u8_enc_key_format_versions 1;
        }

        # internal proxy to live segmenter (nginx-live-module)
        location /ksmp_proxy/ {
            internal;
            proxy_pass http://127.0.0.1:8001/ksmp/;
            subrequest_output_buffer_size 20m;
        }
    }
}

URL Structure

The module parses the file name part of the URL (anything after the last /) in order to service the request. The file name has the following structure -

<prefix>[-<seg_index>[-<part_index>]][-<option1>[-<option2>...]].<extension>

The prefix part must have one of the following values -

• manifest - a DASH manifest, must use mpd extension
• master - an HLS master playlist, must use m3u8 extension
• index - an HLS media playlist, must use m3u8 extension
• init - an initialization segment, used with fMP4 container, must use mp4 extension
• seg - a media segment, the extension must be one of:
  • ts - when using MPEG-TS container (video/audio)
  • m4s - when using fMP4 container (video/audio/subtitle)
  • vtt - when using WebVTT container (subtitle)
• part - a partial media segment (LLHLS), supports the same extensions listed above for media segments
• frame - a single video frame, used when capturing frames, the extension must be jpg
• enc - an encryption key, must use key extension

The <seg_index> parameter is required for media / initialization segment requests. The <seg_index> and <part_index> parameters are required for partial media segment requests. These parameters are not allowed in other types of requests.

The following options are supported -

• s<variant_id> - choose a subset of the available variants. For example, master-s720p-s480p.m3u8 returns only the variants with ids 720p / 480p. Certain types of requests (e.g. manifest.mpd / master.m3u8) support getting multiple variant options, while other requests (e.g. index.m3u8 / seg.ts) require a single variant option.
• v / a / t - choose a subset of the available media types. For example, master-a.m3u8 returns an audio-only stream.

Capture requests use a slightly different structure -

frame-<timestamp>-s<variant_id>[-w<width>][-h<height>].jpg

By default, the timestamp parameter is an absolute timestamp. If the timestamp is prefixed with a minus (-), it is interpreted as an offset relative to the end of the timeline. If the timestamp is prefixed with a plus (+), it is interpreted as an offset relative to the start of the timeline.

The width / height parameters can be used to scale the returned image. When these parameters are not supplied, no scaling will be performed - the returned image will use the original video dimensions. When only one of the parameters is specified, the other dimension is set to a value that retains the aspect ratio of the original video frame.

Configuration Directives

Core Directives

pckg

• syntax: pckg;
• default: ``
• context: location

Enables the media packager in the surrounding location block. Requests to this location will be parsed according the format explained in URL structure.

pckg_uri

• syntax: pckg_uri expr;
• default: ``
• context: http, server, location

Sets the internal uri that should be used to query the segmenter. On every HLS/DASH request that the packager receives, it evaluates the provided expression, and creates an nginx subrequest with the value as its uri. The location referenced by the pckg_uri directive, should use the proxy_pass directive to relay the request to nginx-live-module. The parameter value can contain variables.

pckg_format

• syntax: pckg_format ksmp | sgts;
• default: ksmp
• context: http, server, location

Sets the format of the responses to the packager requests, the following values are supported -

• ksmp - Kaltura Segmented Media Protocol, this is the format returned by nginx-live-module
• sgts - the format nginx-live-module uses for persisting media. This format can be used for recovery purposes, in order to convert persisted files directly to HLS/DASH, without the need to set up a channel using nginx-live-module APIs.

pckg_channel_id

• syntax: pckg_channel_id expr;
• default: ``
• context: http, server, location

Sets the live channel id. The channel id is usually captured from the request uri using a regex location or map (as in the Sample Configuration). The parameter value can contain variables.

pckg_timeline_id

• syntax: pckg_timeline_id expr;
• default: ``
• context: http, server, location

Sets the live timeline id. The timeline id is usually captured from the request uri using a regex location or map (as in the Sample Configuration). The parameter value can contain variables.

pckg_max_segment_index

• syntax: pckg_max_segment_index expr;
• default: ``
• context: http, server, location

Limits the segment indexes returned in manifest requests to the specified value. This parameter can be used to create a live replay of persisted streams - the limit can be raised every few sec, thereby exposing additional segments to the player. The parameter value can contain variables.

pckg_ksmp_max_uncomp_size

• syntax: pckg_ksmp_max_uncomp_size size;
• default: 5m
• context: http, server, location

Sets the maximum uncompressed size that is allowed when parsing compressed KLPF responses.

pckg_expires_static

• syntax: pckg_expires_static sec;
• default: 100d
• context: http, server, location

Sets the value of the Expires and Cache-Control response headers for successful requests in which the response is static (e.g. media segments and initialization segments).

pckg_expires_index

• syntax: pckg_expires_index sec;
• default: 3s
• context: http, server, location

Sets the value of the Expires and Cache-Control response headers for successful requests in which the response contains a list of segments, specifically: HLS index playlists and DASH manifests.

pckg_expires_index_gone

• syntax: pckg_expires_index_gone sec;
• default: 5s
• context: http, server, location

Sets the value of the Expires and Cache-Control response headers for requests that return HTTP status 410 (Gone).

pckg_expires_index_blocking

• syntax: pckg_expires_index_blocking sec;
• default: 30
• context: http, server, location

Sets the value of the Expires and Cache-Control response headers for successful index playlist requests that use the _HLS_msn query parameter.

pckg_expires_master

• syntax: pckg_expires_master sec;
• default: 30
• context: http, server, location

Sets the value of the Expires and Cache-Control response headers for successful master playlist requests.

pckg_last_modified_static

• syntax: pckg_last_modified_static http_time;
• default: Fri, 01 Jan 2010 00:00:00 GMT
• context: http, server, location

Sets the value of the Last-Modified response header for successful requests in which the response is static (e.g. media segments and initialization segments).

pckg_pass_codes

• syntax: pckg_pass_codes off | any | code...;
• default: off
• context: http, server, location

Controls the status code that is returned when the HTTP request to nginx-live-module fails. When the value is off, any error status code returned from nginx-live-module will fail the packager request with 502. When the value is any, any error status code returned from nginx-live-module will propagate to the packager request. Alternatively, a list of specific status codes can be specified, the supported status codes are: 400, 404, 410.

pckg_active_policy

• syntax: pckg_active_policy last | any;
• default: last
• context: http, server, location

Controls which variants are considered active, and returned in manifest requests. When the value is last, only variants which contain the last segment in the timeline are considered active. When the value is any, variants which contain any segment in the timeline are considered active.

pckg_media_type_selector

• syntax: pckg_media_type_selector request | actual;
• default: request
• context: http, server, location

Controls how media type selectors (v/a/t) should be determined for URLs that are returned in manifests. When the value is request, the returned selectors will match the selectors of the request. For example, URLs in the response of master.m3u8 will not contain a selector, while URLs in the response of master-v.m3u8 will contain a video selector (v). When the value is actual, the returned selectors will match the media types that exist in the returned variants. For example, a request for index.m3u8 may return a video selector (v) when the variant is video-only, and it may return an audio selector (a) when the variant is audio-only.

pckg_back_fill

• syntax: pckg_back_fill on | off;
• default: off
• context: http, server, location

Enables or disables back-filling.

Consider a channel with two variants, each with its own video track and audio track - v1/a1, v2/a2. In the first few segments, no media is received for a2, so the segments do not contain this track. Then, at some point, a2 starts publishing. When pckg_back_fill is enabled, requests for segments that did not contain media for a2, will fill the gap by copying the respective media from a1. When pckg_back_fill is disabled, requests for segments that did not contain media for a2, will return only the video track - v2.

An implication of back-filling is that responses for segment requests may change over time.

pckg_media_timestamps

• syntax: pckg_media_timestamps relative | absolute;
• default: relative
• context: http, server, location

When set to relative, the timestamps that are returned in media segments are relative to the start of the period. When set to absolute, the timestamps that are returned in media segments are relative to the epoch.

pckg_empty_segments

• syntax: pckg_empty_segments on | off;
• default: off
• context: http, server, location

When enabled, requests for segments that do not exist on the specific variant/media type will return an empty segment. For example, when the container is MPEG-TS, the response will contain only a PAT and a PMT.

When disabled, requests for segments that do not exist on the specific variant/media type will return a 404 error.

pckg_output_buffer_pool

• syntax: pckg_output_buffer_pool size num;
• default: ``
• context: http, server, location

Pre-allocates num buffers with the specified size for storing output media. The buffer pool can provide a slight performance optimization by avoiding the need to allocate/free the media buffers for every request.

pckg_segment_metadata

• syntax: pckg_segment_metadata expr;
• default: ``
• context: http, server, location

When the provided expression is evaluated to a non-empty string, it is returned as metadata on segment requests. The parameter value can contain variables.

The metadata is encapsulated as an ID3 TEXT frame. When using fMP4 container, the ID3 frame is sent inside an emsg box with the scheme https://developer.apple.com/streaming/emsg-id3. When using MPEG-TS container, the ID3 frame is sent in a private stream (SID 0xbd).

M3u8 Directives (HLS)

pckg_m3u8_low_latency

• syntax: pckg_m3u8_low_latency on | off;
• default: off
• context: http, server, location

Enables or disables low-latency HLS features.

When set to on, this directive is an alias to the following:

pckg_m3u8_mux_segments off;
pckg_m3u8_parts on;
pckg_m3u8_rendition_reports on;

pckg_m3u8_ctl_block_reload on;
pckg_m3u8_ctl_part_hold_back_percent 300;
pckg_m3u8_ctl_skip_boundary_percent 600;

When set to off, this directive is an alias to the following:

pckg_m3u8_mux_segments on;
pckg_m3u8_parts off;
pckg_m3u8_rendition_reports off;

pckg_m3u8_ctl_block_reload off;
pckg_m3u8_ctl_part_hold_back_percent 0;
pckg_m3u8_ctl_skip_boundary_percent 0;

pckg_m3u8_container

• syntax: pckg_m3u8_container auto | mpegts | fmp4;
• default: auto
• context: http, server, location

Sets the container used for media segments.

When set to auto, MPEG-TS container is used by default, however, if any of the following conditions applies, fMP4 container is used instead -

• The channel uses the low latency segmenter - in LLHLS, media is delivered in small parts, using MPEG-TS in this case, can result in a significant overhead in bandwidth.
• Encryption using the cenc scheme is enabled - MPEG-TS does not support this scheme.
• The variant contains an h265/HEVC video track - according to the HLS authoring specification, the container format for HEVC video must be fMP4.

pckg_m3u8_subtitle_format

• syntax: pckg_m3u8_subtitle_format webvtt | imsc;
• default: webvtt
• context: http, server, location

Sets the container used for delivering subtitles -

• webvtt - the segments are WebVTT file sections.
• imsc - the segments are TTML sections, encapsulated in an fMP4 container.

pckg_m3u8_mux_segments

• syntax: pckg_m3u8_mux_segments on | off | expr;
• default: on
• context: http, server, location

When the provided expression evaluates to on, video and audio tracks are muxed together in the same segments.

When the provided expression evaluates to off, video and audio tracks are delivered in separate segments. The master playlist uses #EXT-X-MEDIA to connect the video stream and the audio stream. The parameter value can contain variables.

pckg_m3u8_parts

• syntax: pckg_m3u8_parts on | off;
• default: off
• context: http, server, location

When enabled, the module outputs parts in index playlist responses (using #EXT-X-PART / #EXT-X-PRELOAD-HINT tags).

pckg_m3u8_rendition_reports

• syntax: pckg_m3u8_rendition_reports on | off;
• default: off
• context: http, server, location

When enabled, the module outputs rendition reports in index playlist responses (using #EXT-X-RENDITION-REPORT tags).

pckg_m3u8_program_date_time

• syntax: pckg_m3u8_program_date_time on | off | expr;
• default: on
• context: http, server, location

When enabled, the module output an #EXT-X-PROGRAM-DATE-TIME tag for each period, containing its absolute timestamp. The parameter value can contain variables.

pckg_m3u8_ctl_block_reload

• syntax: pckg_m3u8_ctl_block_reload on | off | expr;
• default: ``
• context: http, server, location

When enabled, the module includes the CAN-BLOCK-RELOAD=YES attribute in the returned #EXT-X-SERVER-CONTROL tag. The parameter value can contain variables.

pckg_m3u8_ctl_part_hold_back_percent

• syntax: pckg_m3u8_ctl_part_hold_back_percent num | expr;
• default: 300
• context: http, server, location

Sets the value of the PART-HOLD-BACK attribute in the returned #EXT-X-SERVER-CONTROL tag. The value is expressed as a percent of the part duration defined in the segmenter. The parameter value can contain variables.

pckg_m3u8_ctl_skip_boundary_percent

• syntax: pckg_m3u8_ctl_skip_boundary_percent num | expr;
• default: 0
• context: http, server, location

Sets the value of the CAN-SKIP-UNTIL attribute in the returned #EXT-X-SERVER-CONTROL tag. The value is expressed as a percent of the target duration of the timeline. The parameter value can contain variables.

pckg_m3u8_enc_output_iv

• syntax: pckg_m3u8_enc_output_iv on | off;
• default: on
• context: http, server, location

When enabled, the module outputs the IV attribute in returned #EXT-X-KEY / #EXT-X-SESSION-KEY tags.

pckg_m3u8_enc_key_uri

• syntax: pckg_m3u8_enc_key_uri expr;
• default: ``
• context: http, server, location

Sets the value of the URI attribute of the #EXT-X-KEY tag. The parameter value can contain variables.

The provided expression may be evaluated multiple times, depending on the value of pckg_enc_scope. The variables pckg_variant_id / pckg_media_type can be used in the expression to produce different URLs, when the encryption scope is not channel.

When encryption is enabled, and this directive is not used, a URI is generated automatically:

• If pckg_enc_scheme is set to cenc, the URI will contain the PSSH boxes provided in pckg_enc_json, base64 encoded.
• Otherwise, URI will return an enc.key URL, according to the configured pckg_enc_scope.

pckg_m3u8_enc_key_format

• syntax: pckg_m3u8_enc_key_format str;
• default: ``
• context: http, server, location

Sets the value of the KEYFORMAT attribute of the #EXT-X-KEY tag.

pckg_m3u8_enc_key_format_versions

• syntax: pckg_m3u8_enc_key_format_versions str;
• default: ``
• context: http, server, location

Sets the value of the KEYFORMATVERSIONS attribute of the #EXT-X-KEY tag.

MPD Directives (DASH)

pckg_mpd_profiles

• syntax: pckg_mpd_profiles expr;
• default: urn:mpeg:dash:profile:isoff-live:2011
• context: http, server, location

Sets the value of the profiles attribute of the MPD element. The parameter value can contain variables.

pckg_mpd_subtitle_format

• syntax: pckg_mpd_subtitle_format wvtt | stpp;
• default: wvtt
• context: http, server, location

Sets the container used for delivering subtitles -

• wvtt - the segments are WebVTT sections, encapsulated in an fMP4 container.
• stpp - the segments are TTML sections, encapsulated in an fMP4 container.

pckg_mpd_pres_delay_segments

• syntax: pckg_mpd_pres_delay_segments num;
• default: 3
• context: http, server, location

Sets the segment according to which the suggestedPresentationDelay attribute of the MPD element is set. The value is expressed as a number of segments, starting from the end of the timeline.

For example, if the segments of the timeline are numbered as 1 .. N, when using the default value of 3, the suggested presentation delay will be: now - segment_start_time[N - 2].

MPEG-TS Directives

pckg_mpegts_interleave_frames

• syntax: pckg_mpegts_interleave_frames on | off;
• default: off
• context: http, server, location

When enabled, the MPEG-TS muxer interleaves frames of different streams (video / audio). When disabled, on every switch between audio / video the muxer flushes the MPEG TS packet.

Enabling this setting can reduce the muxing overhead of the MPEG-TS packaging.

pckg_mpegts_align_frames

• syntax: pckg_mpegts_align_frames on | off;
• default: on
• context: http, server, location

When enabled, every video / audio frame is aligned to MPEG-TS packet boundary, padding is added as needed.

Disabling this setting can reduce the muxing overhead of the MPEG-TS packaging.

Encryption Directives

pckg_enc_scheme

• syntax: pckg_enc_scheme none | aes-128 | cbcs | cenc;
• default: none
• context: http, server, location

Sets the encryption scheme that is used to encrypt media segments.

When using the MPEG-TS container:

• the cbcs scheme follows the HLS Sample Encryption specification.
• the cenc scheme is not supported.

pckg_enc_scope

• syntax: pckg_enc_scope channel | media_type | variant | track;
• default: channel
• context: http, server, location

Sets the scope of the encryption keys, the following values are supported:

• channel - a single encryption key is used to encrypt all the tracks of the channel.
• media_type - at most 2 encryption keys are used - one for video, one for audio.
• variant - an encryption key is assigned for each variant.
• track - an encryption key is assigned for each track.

pckg_enc_key_seed

• syntax: pckg_enc_key_seed expr;
• default: $pckg_channel_id
• context: http, server, location

Sets a seed that is used to generate encryption keys. The parameter value can contain variables.

The provided expression may be evaluated multiple times, depending on the value of pckg_enc_scope. The variables pckg_variant_id / pckg_media_type can be used in the expression to produce multiple seeds, when the encryption scope is not channel.

pckg_enc_iv_seed

• syntax: pckg_enc_iv_seed expr;
• default: ``
• context: http, server, location

Sets a seed that is used to generate encryption initialization vectors (IVs). The parameter value can contain variables.

The provided expression may be evaluated multiple times, depending on the value of pckg_enc_scope. The variables pckg_variant_id / pckg_media_type can be used in the expression to produce multiple seeds, when the encryption scope is not channel.

If this directive is not set, the expression provided in pckg_enc_key_seed is used by default.

pckg_enc_serve_key

• syntax: pckg_enc_serve_key on | off;
• default: on
• context: http, server, location

When enabled, the module serves the encryption keys in the clear, when getting enc.key requests.

pckg_enc_json

• syntax: pckg_enc_json expr;
• default: ``
• context: http, server, location

Sets the parameters used for encryption. The parameter value can contain variables.

The provided expression may be evaluated multiple times, depending on the value of pckg_enc_scope. The variables pckg_variant_id / pckg_media_type can be used in the expression to map to the different JSONs, when the encryption scope is not channel.

This directive is used mostly for enabling DRM, therefore, by default, it disables pckg_enc_serve_key (this behavior can be overridden by explicitly setting pckg_enc_serve_key on; before pckg_enc_json in the same configuration block)

The provided expression must evaluate to a JSON object, containing the following fields:

• key - string, required, the encryption key (128 bit) in base64 encoding
• key_id - string, optional, the encryption key identifier (128 bit) in base64 encoding
• iv - string, optional, the encryption initialization vector (128 bit) in base64 encoding
• systems - object, optional, the keys are DRM system IDs (GUIDs), the values are strings containing base64 encoded PSSH (Protection System Specific Header).

Capture Directives

pckg_capture

• syntax: pckg_capture on | off;
• default: off
• context: http, server, location

Enables / disables the capture functionality.

Capture requests are more CPU-intensive than requests for serving media, therefore, they are disabled by default.

pckg_capture_redirect

• syntax: pckg_capture_redirect on | off;
• default: on
• context: http, server, location

When enabled, capture requests that use relative timestamps, redirect to a URL that uses the corresponding absolute timestamp.

Requests that use timestamps relative to the end of the live stream can return different images when the stream is live, while requests that use absolute timestamps return a static image. The use of redirect on relative requests enables the caching of the resulting images (by a CDN / proxy).

pckg_capture_granularity

• syntax: pckg_capture_granularity frame | key;
• default: frame
• context: http, server, location

When set to frame, capture requests use the frame that is closest to the requested timestamp.

When set to key, capture requests use the keyframe that is closest to the requested timestamp.

This directive provides a trade-off between resource usage and capture accuracy - setting the value to key reduces CPU usage (only one frame is decoded) and internal bandwidth (nginx-live-module returns a single frame).

Closed Captions Directives

pckg_captions_json

• syntax: pckg_captions_json expr;
• default: ``
• context: http, server, location

Sets the parameters of the closed captions embedded in the video tracks of the channel. The parameter value can contain variables.

The provided expression must evaluate to a JSON object. The keys must be closed caption channel ids - cc1 .. cc4 for 608 captions, service1 .. service63 for 708 captions. The values must be objects containing the following fields:

• label - string, required, a "friendly" name for the closed captions channel (e.g. English).
• lang - string, optional, an RFC5646 language code (e.g. en).
• is_default - boolean, optional, sets the values of the AUTOSELECT / DEFAULT attributes of the #EXT-X-MEDIA tag in HLS.

Session Data Directives

pckg_session_data_json

• syntax: pckg_session_data_json expr;
• default: ``
• context: http, server, location

Sets the "session data" of the channel, returned as #EXT-X-SESSION-DATA tags in master playlist responses. The parameter value can contain variables.

The provided expression must evaluate to a JSON array containing objects. Each object in the array, is rendered as an #EXT-X-SESSION-DATA tag, and contains the following fields:

• id - string, required, sets the DATA-ID attribute.
• value - string, optional, sets the VALUE attribute.
• uri - string, optional, sets the URI attribute.
• lang - string, optional, sets the LANGUAGE attribute.

The object must contain either value or uri, but not both.

Embedded Variables

This module supports the following embedded variables:

• $pckg_channel_id - the channel id, as provided to the pckg_channel_id directive.

• $pckg_timeline_id - the timeline id, as provided to the pckg_timeline_id directive.

• $pckg_variant_ids - the variant ids supplied on the request URL, if multiple values are provided, they are delimited with an hyphen (-).

• $pckg_variant_id - the id of the variant currently being initialized, intended for use in pckg_m3u8_enc_key_uri, pckg_enc_key_seed, pckg_enc_iv_seed, pckg_enc_json.

• $pckg_media_type - the media type currently being initialized (video / audio), intended for use in pckg_m3u8_enc_key_uri, pckg_enc_key_seed, pckg_enc_iv_seed, pckg_enc_json.

• $pckg_err_code - evaluates to the KSMP error code returned from nginx-live-module, the possible values are defined in ngx_ksmp_errs_x.h.

• $pckg_err_msg - evaluates to the KSMP error message returned from nginx-live-module.

• $pckg_part_duration - when the channel uses the low latency segmenter, evaluates to the part duration in milliseconds. Evaluates to zero if the channel uses the default segmenter.

• $pckg_last_part - the index of the last part returned in an index playlist request, uses the format <segment_index>:<part_index>.

• $pckg_segment_dts - the initial timestamp (dts) of the segment in milliseconds. When the segment contains multiple tracks, returns the dts of the first track that contains frames.

• $pckg_var_{name} - returns the value of the live channel variable {name}, as returned from nginx-live-module.

• $pckg_upstream_{name} - returns the value of the $upstream_{name} variable, when evaluated on the KSMP subrequest. For example:

  • $pckg_upstream_status returns the status code of the HTTP request that was sent to nginx-live-module.
  • $pckg_upstream_http_block_duration returns the value of the Block-Duration header returned from nginx-live-module.

  See the documentation of the nginx upstream module for the list of upstream_ variables that can be used.