Function video_packet_from_ffmpeg_in 

pub fn video_packet_from_ffmpeg_in(
    packet: Packet,
    time_base: Timebase,
    limits: PacketLimits,
) -> Result<Option<VideoPacket<VideoPacketExtra, FfmpegBuffer>>, PacketBufferError>

[video_packet_from_ffmpeg_as] on the view lane, with the stream’s timebase stamped onto every timestamp.

Takes the packet by value, and that is the safety property, not a style choice. The program below is the alias this signature forbids — it was accepted when the parameter was a reference, and data_mut handed out a &mut [u8] over bytes the returned carrier was still lending as &[u8]:

use ffmpeg_next::packet::Mut;
use mediadecode::Timebase;
use mediadecode_ffmpeg::{PacketLimits, video_packet_from_ffmpeg_in};

let mut packet = ffmpeg_next::Packet::copy(&[0u8; 64]);
let viewed = video_packet_from_ffmpeg_in(packet, Timebase::default(), PacketLimits::default());
// The source is gone, so this cannot be written.
let _aliased = packet.data_mut();

A caller who wants to keep the packet wants the owned lane, which copies and may therefore borrow: owned_video_packet_from_ffmpeg_in.