fix: force h266parse for vvdec #312
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When `avdec_h266` and `vvdec` are installed with next priorities and sink caps (values at 1.26): ``` avdec_h266: Factory Details: avdec_h266: Rank primary (256) avdec_h266: Long-name libav VVC (Versatile Video Coding) decoder avdec_h266: Klass Codec/Decoder/Video avdec_h266: Description libav vvc decoder avdec_h266: Author Wim Taymans <[email protected]>, Ronald Bultje <[email protected]>, Edward Hervey <[email protected]> avdec_h266: Documentation https://gstreamer.freedesktop.org/documentation/libav/avdec_h266.html ... avdec_h266: Pad Templates: avdec_h266: SINK template: 'sink' avdec_h266: Availability: Always avdec_h266: Capabilities: avdec_h266: video/x-h266 avdec_h266: alignment: au avdec_h266: stream-format: { (string)vvc1, (string)vvi1, (string)byte-stream } ... ... ... vvdec: Factory Details: vvdec: Rank secondary (128) vvdec: Long-name VVdeC VVC/H.266 Decoder vvdec: Klass Codec/Decoder/Video vvdec: Description Decode VVC/H.266 video streams with VVdeC vvdec: Author Carlos Bentzen <[email protected]> vvdec: Documentation https://gstreamer.freedesktop.org/documentation/vvdec/#vvdec-page ... vvdec: Pad Templates: vvdec: SINK template: 'sink' vvdec: Availability: Always vvdec: Capabilities: vvdec: video/x-h266 vvdec: stream-format: byte-stream vvdec: alignment: au ``` Note: more the greater rank in avdec_h266 and different vvdec sink caps ara a subset of avdec_h266 sink caps. Using parsebin doesn't work. The parsebin element was desinged to be used with playbin and uses all the GST_ELEMENT_FACTORY_TYPE_DECODABLE factories avaliable to define the caps to use (note gst_parse_bin_update_factories_list). Other generic solution would be to use GST_PLUGIN_FEATURE_RANK=%targetdecoder%:MAX to be sure parsebin uses the correct decoder, but it requires to extract the decoder element from the decoder_bin. ``` gst-launch-1.0 --no-fault filesrc location=JVET-VVC_draft6/DCI_A_Tencent_3/DCI_A_Tencent_3.bit ! parsebin ! vvdec ! video/x-raw ! fakesink Setting pipeline to PAUSED ... Pipeline is PREROLLING ... Redistribute latency... ERROR: from element /GstPipeline:pipeline0/GstParseBin:parsebin0/GstH266Parse:h266parse0: Internal data stream error. Additional debug info: ../gstreamer/subprojects/gstreamer/libs/gst/base/gstbaseparse.c(3731): gst_base_parse_loop (): /GstPipeline:pipeline0/GstParseBin:parsebin0/GstH266Parse:h266parse0: streaming stopped, reason not-linked (-1) ERROR: pipeline doesn't want to preroll. Setting pipeline to NULL ... Freeing pipeline ... ```
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Pull Request Overview
This PR fixes a decoding pipeline issue for the VVdeC H.266 decoder by explicitly adding h266parse to ensure proper stream parsing. The problem occurs when both avdec_h266 (higher rank) and vvdec (lower rank) are installed - parsebin selects avdec_h266 instead of vvdec, causing a not-linked error due to incompatible caps negotiation.
- Adds explicit
h266parseparser toGStreamerVVdeCH266Decoderclass
Contributor
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I have verified in my environment that this change does not affect regression |
rsanchez87
approved these changes
Oct 27, 2025
mdimopoulos
approved these changes
Oct 27, 2025
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When
avdec_h266andvvdecare installed with next priorities and sink caps (values at 1.26):Note: more the greater rank in avdec_h266 and different vvdec sink caps ara a subset of avdec_h266 sink caps.
Using parsebin doesn't work. The parsebin element was desinged to be used with playbin and uses all the GST_ELEMENT_FACTORY_TYPE_DECODABLE factories avaliable to define the caps to use (note gst_parse_bin_update_factories_list). Other generic solution would be to use GST_PLUGIN_FEATURE_RANK=%targetdecoder%:MAX to be sure parsebin uses the correct decoder, but it requires to extract the decoder element from the decoder_bin.