Streams

Stream collections

class av.container.streams.StreamContainer

Bases: object

A tuple-like container of Stream.

# There are a few ways to pulling out streams.
first = container.streams[0]
video = container.streams.video[0]
audio = container.streams.get(audio=(0, 1))

Dynamic Slicing

StreamContainer.get(streams=None, video=None, audio=None, subtitles=None, data=None)

Get a selection of Stream as a list.

Positional arguments may be int (which is an index into the streams), or list or tuple of those:

# Get the first channel.
streams.get(0)

# Get the first two audio channels.
streams.get(audio=(0, 1))

Keyword arguments (or dicts as positional arguments) as interpreted as (stream_type, index_value_or_set) pairs:

# Get the first video channel.
streams.get(video=0)
# or
streams.get({'video': 0})

Stream objects are passed through untouched.

If nothing is selected, then all streams are returned.

Typed Collections

These attributes are preferred for readability if you don’t need the dynamic capabilities of get():

StreamContainer.video

A tuple of VideoStream.

StreamContainer.audio

A tuple of AudioStream.

StreamContainer.subtitles

A tuple of SubtitleStream.

StreamContainer.data

A tuple of DataStream.

StreamContainer.other

A tuple of Stream

Streams

class av.stream.Stream

Bases: object

A single stream of audio, video or subtitles within a Container.

>>> fh = av.open(video_path)
>>> stream = fh.streams.video[0]
>>> stream
<av.VideoStream #0 h264, yuv420p 1280x720 at 0x...>

This encapsulates a CodecContext, located at Stream.codec_context. Attribute access is passed through to that context when attributes are missing on the stream itself. E.g. stream.options will be the options on the context.

Basics

Stream.type

The type of the stream.

Examples: 'audio', 'video', 'subtitle'.

Type

str

Stream.codec_context

Stream.id

The format-specific ID of this stream.

Type

int

Stream.index

The index of this stream in its Container.

Type

int

Transcoding

Stream.encode(frame=None)

Encode an AudioFrame or VideoFrame and return a list of Packet.

Returns

list of Packet.

See also

This is mostly a passthrough to CodecContext.encode().

Stream.decode(packet=None)

Decode a Packet and return a list of AudioFrame or VideoFrame.

Returns

list of Frame subclasses.

See also

This is mostly a passthrough to CodecContext.decode().

Timing

See also

Time for a discussion of time in general.

Stream.time_base

The unit of time (in fractional seconds) in which timestamps are expressed.

Type

Fraction or None

Stream.start_time

The presentation timestamp in time_base units of the first frame in this stream.

Type

int or None

Stream.duration

The duration of this stream in time_base units.

Type

int or None

Stream.frames

The number of frames this stream contains.

Returns 0 if it is not known.

Type

int

Frame Rates

These attributes are different ways of calculating frame rates.

Since containers don’t need to explicitly identify a frame rate, nor even have a static frame rate, these attributes are not guaranteed to be accurate. You must experiment with them with your media to see which ones work for you for your purposes.

Whenever possible, we advise that you use raw timing instead of frame rates.

Stream.average_rate

The average frame rate of this video stream.

This is calculated when the file is opened by looking at the first few frames and averaging their rate.

Type

Fraction or None

Stream.base_rate

The base frame rate of this stream.

This is calculated as the lowest framerate at which the timestamps of frames can be represented accurately. See AVStream.r_frame_rate for more.

Type

Fraction or None

Stream.guessed_rate

The guessed frame rate of this stream.

This is a wrapper around av_guess_frame_rate, and uses multiple heuristics to decide what is “the” frame rate.

Type

Fraction or None

Others

Stream.profile

The profile of this stream.

Type

str

Stream.language

The language of the stream.

Type

:class:str or None