Skip to content

v19.0.0

Choose a tag to compare

View all tags
@WyattBlue WyattBlue released this 29 Sep 17:31
· 5 commits to master since this release
v19.0.0
b484ef4

Major

  • Drop support for Python 3.11. Binary wheels are now built for Python 3.12 and later.
  • Remove the undocumented CodecContext.hwaccel attribute. It held the HWAccel settings object passed in, not the live device context; use CodecContext.is_hwaccel to check whether hardware acceleration is in use.
  • Rational attributes (time_base, average_rate, base_rate, guessed_rate, framerate, rate, sample_aspect_ratio, and display_aspect_ratio) now return av.AVRational rather than fractions.Fraction, and are never None: an unset value is the falsy AVRational(0, 1). Test them with if not stream.time_base: instead of is None. Setters still accept a fractions.Fraction.
  • Closing an OutputContainer now frees its context, so using one afterwards raises Container is not open instead of continuing against a finished file. Muxing has no avformat_close_input() to do this for it, so add_stream(), mux(), start_encoding() and the rest kept working after close(), and streams held from it stayed readable.
  • Remove Capabilities.hwaccel, Capabilities.hwaccel_vdpau, and Capabilities.neg_linesizes, none of which FFmpeg defines any more.
  • Remove the metadata_encoding and metadata_errors arguments to av.open, and the matching attributes. Metadata is now always read and written as UTF-8 with surrogateescape, which is byte exact: a tag in another encoding survives as surrogates and is recovered per key with value.encode("utf-8", "surrogateescape").decode("cp1251"). Previously one encoding had to be chosen for a whole container, so a file mixing encodings across tags could not be represented at all.
  • Remove the stream_options argument to av.open and the matching attribute. They only ever reached avformat_find_stream_info(), and only for formats that expose their streams before it runs, so they raised for MPEG and friends; output containers rejected them outright. Pass options for every stream, set stream.codec_context.options for one, and Container.add_stream(..., options={}) when writing.

Features

  • av.dump_codecs() now lists every codec FFmpeg knows of rather than only those with an encoder or a decoder, so data and attachment codecs appear, matching ffmpeg -codecs. Its legend gains the ..D... and ..T... media types.
  • ContainerFormat.fixed_framesize reports whether a format wants fixed size audio frames.
  • CodecContext exposes more of AVCodecContext: pkt_timebase, frame_num, active_thread_type, bits_per_raw_sample, compression_level, rc_buffer_size, min_bit_rate, a setter for max_bit_rate, the audio initial_padding, trailing_padding, and seek_preroll, and stats_in/stats_out for two-pass encoding. VideoCodecContext gains chroma_sample_location, refs, and mb_decision; AudioCodecContext gains block_align.
  • CodecContext.coded_side_data and CodecContext.decoded_side_data expose the context's global side data as dicts of bytes, keyed by packet side data name and Type respectively. Stream wide HDR metadata, such as mastering display and content light level, arrives in decoded_side_data once a frame has been decoded.
  • VideoFrame.chroma_location exposes AVFrame.chroma_location, the position of the chroma samples relative to the luma samples, and the new ChromaLocation enum names its values. Only the codec context side of the field was wrapped, as VideoCodecContext.chroma_sample_location, so the siting a decoder actually reported per frame could not be read at all. Each property mirrors its C field name, which FFmpeg spells differently on the two structs.
  • Enums gained the members FFmpeg has since added: Properties.FIELDS, Properties.ENHANCEMENT, PixFmtLoss.EXCESS_RESOLUTION, PixFmtLoss.EXCESS_DEPTH, Flags2.icc_profiles, format.Flags.experimental, Interpolation.STRICT, Interpolation.UNSTABLE, ColorTrc.V_LOG, ColorPrimaries.V_GAMUT, the LCEVC, VIEW_ID, THREE_D_REFERENCE_DISPLAYS, and EXIF members of sidedata.Type, and the exif, dynamic_hdr_smpte_2094_app5, and hevc_conf packet side data names.

Fixes

  • Frame.side_data and PacketSideData.data_type no longer raise on side data types FFmpeg has added since PyAV last listed them. The packet side data names were missing three, so reading, say, the AV_PKT_DATA_HEVC_CONF an HEVC stream in MP4 or Matroska carries raised IndexError. A frame side data type that no sidedata.Type member names, which is anything a newer FFmpeg than PyAV was built against added, now becomes an UNKNOWN_<value> member rather than raising ValueError.
  • CodecContext.bit_rate_tolerance returns its value instead of always None; the getter was missing its return.
  • A rejected add_stream() or add_mux_stream() no longer breaks the container.
  • InputContainer.size returns None when the size cannot be determined rather than the negative AVERROR it was passing through, which read as a plausible byte count. A non-seekable input, such as a pipe, reported -78.
  • av.dump_codecs() no longer drops the canonical names h264, hevc, av1, dirac, and ilbc, each of which was overwritten by the row of whichever encoder it resolved to.
  • FilterLink.input and FilterLink.output now follow the filters the graph auto-inserts while configuring. They cached the pad they first resolved, so reading one before Graph.configure() reported the filter the link no longer pointed at.
  • Fix a segfault when a FilterLink outlives its Graph. It held the graph by weak reference and dereferenced AVFilterLink before consulting it, so link.input and link.output read freed memory. It now holds the graph, as a FilterContext already did.
  • Reading a Stream or its index_entries after the container is closed now raises instead of reading freed memory, since avformat_close_input() frees the underlying AVStream. Holding an index_entries also keeps its container alive, and an IndexEntry is a copy, so it stays readable after the close and is unaffected by the demuxer reallocating the index.
  • Attaching one object to the opaque of more than one frame or packet no longer loses it. The objects were keyed by id(), so every holder shared an entry and whichever was freed first took it away from the rest.
  • Frame.side_data now satisfies the Mapping protocol it advertises: iteration yields Type keys, so items(), keys(), and values() work instead of raising KeyError. Values remain reachable positionally by an integer or, for the first time, a slice. Its type stub was a TypedDict with a single literal key, and is now SideDataContainer.
  • Fix crashes from indexes that were turned into C pointer arithmetic without being range checked. MotionVectors[i] only checked the upper bound, so a negative index read off the front of the buffer (mvs[-1] now returns the last vector, as with any sequence); VideoFormatComponent and AudioPlane accepted any index at all; and BitmapSubtitlePlane and VideoBlockParams were missing their lower bounds.
  • Frames returned by flushing a codec context directly (CodecContext.decode() with no packet) now carry the stream's time_base instead of None.
  • VideoFrame.reformat() (and so to_ndarray(format=...), to_rgb(), to_image()) now shares one SwsContext per thread instead of allocating one per frame. FFmpeg 8's swscale retains megabytes of graph state per context, which showed up as large RSS growth when many frames were alive at once.
  • Writing to a network URL no longer blocks every other Python thread, and timeout now applies to opening an output container. avio_open(), avformat_write_header(), av_write_trailer(), and avio_closep() held the GIL, so an unreachable RTMP server froze the whole process, and the interrupt callback was only installed for demuxing, so nothing could end the wait. OutputContainer.close now raises rather than freeing a context another thread is still muxing or closing. By @adrianrfreedman in (#2412).
  • timeout now applies to muxing and closing an output container, not just to opening it. Only opening armed the interrupt callback, so a peer that accepted the connection and then stopped reading left av_interleaved_write_frame() and av_write_trailer() blocked forever. Each mux gets the full timeout, and a close shares one across writing the trailer and flushing, so neither can outlast it. Only unseekable outputs are covered: writing a seekable file takes as long as the file is big, so a deadline meant for a peer would abandon it part-written. By @adrianrfreedman in (#2414).
  • HWAccel.create now passes flags on to the context it creates. They were dropped, so av_hwdevice_ctx_create() always got 0 and CUDA's AV_CUDA_USE_PRIMARY_CONTEXT could not be requested through them.

New Contributors

Full Changelog: v18.1.0...v19.0.0

Contributors

adrianrfreedman, threexc, and 3 other contributors
Assets 21
Loading