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126 lines
4.7 KiB
Markdown
126 lines
4.7 KiB
Markdown
---
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short-description: Tool to test GStreamer components
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...
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# gst-validate-transcoding
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`gst-validate-transcoding` is tool to create media files transcoding
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pipelines running inside the GstValidate monitoring infrastructure.
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You can for example transcode any media file to Vorbis audio + VP8 video
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in a WebM container by doing:
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gst-validate-transcoding-GST_API_VERSION file:///./file.ogg file:///.../transcoded.webm -o 'video/webm:video/x-vp8:audio/x-vorbis'
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`gst-validate-transcoding` will list every issue encountered during the
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execution of the transcoding operation in a human readable report like
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the one below:
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issue : buffer is out of the segment range Detected on theoradec0.srcpad
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at 0:00:00.096556426 Details : buffer is out of segment and shouldn't be
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pushed. Timestamp: 0:00:25.000 - duration: 0:00:00.040 Range:
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0:00:00.000 - 0:00:04.520 Description : buffer being pushed is out of
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the current segment's start-stop range. Meaning it is going to be
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discarded downstream without any use
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The return code of the process will be 18 in case a `CRITICAL` issue has
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been found.
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## The encoding profile serialization format
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This is the serialization format of a [GstEncodingProfile](GstEncodingProfile).
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Internally the transcoding application uses [GstEncodeBin](encodebin).
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`gst-validate-transcoding-GST_API_VERSION` uses its own serialization
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format to describe the [`GstEncodeBin.profile`](encodebin:profile) property of the
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encodebin.
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The simplest serialized profile looks like:
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muxer_source_caps:videoencoder_source_caps:audioencoder_source_caps
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For example to encode a stream into a WebM container, with an OGG audio
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stream and a VP8 video stream, the serialized [GstEncodingProfile](GstEncodingProfile)
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will look like:
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video/webm:video/x-vp8:audio/x-vorbis
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You can also set the preset name of the encoding profile using the
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caps+preset\_name syntax as in:
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video/webm:video/x-vp8+youtube-preset:audio/x-vorbis
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Moreover, you can set the [presence](gst_encoding_profile_set_presence) property
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of an encoding profile using the `|presence` syntax as in:
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video/webm:video/x-vp8|1:audio/x-vorbis
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This field allows you to specify how many times maximum a
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[GstEncodingProfile](GstEncodingProfile) can be used inside an encodebin.
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You can also use the `restriction_caps->encoded_format_caps` syntax to
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specify the [restriction caps](GstEncodingProfile:restriction-caps)
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to be set on a [GstEncodingProfile](GstEncodingProfile). It
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corresponds to the restriction [GstCaps](GstCaps) to apply before the encoder
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that will be used in the profile. The fields present in restriction caps
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are properties of the raw stream (that is, before encoding), such as
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height and width for video and depth and sampling rate for audio. This
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property does not make sense for muxers.
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To force a video stream to be encoded with a Full HD resolution (using
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WebM as the container format, VP8 as the video codec and Vorbis as the
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audio codec), you should use:
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video/webm:video/x-raw,width=1920,height=1080->video/x-vp8:audio/x-vorbis
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### Some serialized encoding formats examples:
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MP3 audio and H264 in MP4:
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<div class="informalexample">
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video/quicktime,variant=iso:video/x-h264:audio/mpeg,mpegversion=1,layer=3
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</div>
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Vorbis and theora in OGG:
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<div class="informalexample">
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application/ogg:video/x-theora:audio/x-vorbis
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</div>
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AC3 and H264 in MPEG-TS:
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<div class="informalexample">
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video/mpegts:video/x-h264:audio/x-ac3
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</div>
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# Invocation
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`gst-validate-transcoding` takes and input URI and an output URI, plus a
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few options to control how transcoding should be tested.
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## Options
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* `--set-scenario`: Let you set a scenario, it can be a full path to a scenario file or
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the name of the scenario (name of the file without the `.scenario`
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extension).
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* `-l`, `--list-scenarios`: List the avalaible scenarios that can be run.
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* `--scenarios-defs-output-file`: The output file to store scenarios details. Implies
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`--list-scenario`.
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* `-t`, `--inspect-action-type`: Inspect the avalaible action types with which to write scenarios if
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no parameter passed, it will list all avalaible action types
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otherwize will print the full description of the wanted types.
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* `--set-configs`: Let you set a config scenario. The scenario needs to be set as
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`config`. You can specify a list of scenarios separated by `:`. It
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will override the GST\_VALIDATE\_SCENARIO environment variable.
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* `-e`, `--eos-on-shutdown`: If an EOS event should be sent to the pipeline if an interrupt is
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received, instead of forcing the pipeline to stop. Sending an EOS
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will allow the transcoding to finish the files properly before
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exiting.
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* `-r`, `--force-reencoding`: Whether to try to force reencoding, meaning trying to only remux if
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possible, defaults to `TRUE`.
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