Struct ParametersChannelMap 

pub struct ParametersChannelMap { /* private fields */ }

Payload for DemuxError::ParametersChannelMap.

A channel layout declared AV_CHANNEL_ORDER_CUSTOM without the map that order requires.

This one is a crash, not a curiosity. For a custom order, av_channel_layout_copy — which is how avcodec_parameters_to_context moves a layout into a decoder’s context — does

dst->u.map = av_malloc_array(src->nb_channels, sizeof(*dst->u.map));
if (!dst->u.map)
    return AVERROR(ENOMEM);
memcpy(dst->u.map, src->u.map, src->nb_channels * sizeof(*src->u.map));

with no null check on src->u.map — verified against FFmpeg n9.0. A layout that names channels it has no map for therefore makes libavcodec memcpy from a null pointer the moment a decoder opens from it.

So the mirror refuses such a layout at the door rather than reproducing it. An earlier draft carried it through, on the argument that a malformed layout in should be a malformed layout out — the round trip is faithful either way, and the parity comparator agreed. That symmetry was the wrong test: faithfully reproducing a shape whose only consumer dereferences null is not fidelity, it is forwarding a crash. Refusing is the same fail-closed answer extras::measure_parameters gives a channel order it has never heard of.

Implementations

impl ParametersChannelMap

pub const fn new(stream_index: usize, channels: i32) -> Self

Constructs a ParametersChannelMap payload.

pub const fn stream_index(&self) -> usize

The AVStream.index whose layout was malformed.

pub const fn channels(&self) -> i32

The nb_channels the layout declared with no map to describe them.

Trait Implementations

impl Clone for ParametersChannelMap

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ParametersChannelMap

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for ParametersChannelMap

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for ParametersChannelMap

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<ParametersChannelMap> for DemuxError

fn from(source: ParametersChannelMap) -> Self

Converts to this type from the input type.

impl From<ParametersChannelMap> for Error

fn from(source: ParametersChannelMap) -> Self

Converts to this type from the input type.