By default, framerate is unchanged (MP4 24fps stays 24fps in 3GP). If you need to change it (e.g. interlaced 29.97 → progressive 30fps), use the framerate option, which handles 3:2 pulldown and deinterlacing in the same pass.
MP4 和 3GP 之间的文件大小区别是多少?
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Same-codec re-muxes (e.g. MP4 → 3GP where both use H.264) produce nearly-identical sizes. Codec changes can swing the size dramatically: H.264 → H.265 typically halves the file at the same visual quality; H.264 → VP9 is roughly comparable.
iPhone / Android / Smart TV 上的 3GP 文件会播放吗?
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MP4 / H 264 在各地的本地游戏。 MOV / H 264 在苹果设备和大多数智能电视上玩, 但不在老的Android上玩。 MKV 在iOS上需要 VLC。 高级选项包括“ 设备兼容性” 预设, 选择目标设备的最安全编码/ 容器组合 。
Not in the same step — use /video-trim/ or /video-cutter/ to trim before converting, then queue the MP4 → 3GP step. Trimming and converting in series is faster than re-encoding the whole file just to crop.