MP4(3)

💖 MP4 — the MP4 File Format Library, bestie 💖

okay so this is a page from the MP4 File Format Library manual, section 3. It's giving "codec internals but make it cute." Buckle up, we're getting your elementary stream config and we're doing it together. 🦋

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✨ NAME ✨

MP4GetTrackESConfiguration — get the elementary stream (ES) configuration of a track

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✨ SYNTAX ✨

#include <mp4.h>

void MP4GetTrackESConfiguration(
     MP4FileHandle hFile,
     MP4TrackId trackId
     u_int8_t** ppConfig,
     u_int32_t* pConfigSize
)

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✨ ARGUMENTS ✨

• hFile — the mp4 file we're doing the operation on. which file, bestie? this one. 🎀
• trackId — the track whose ES configuration you're craving. pick your track, we're going in.
• ppConfig — a pointer to a pointer variable, and this one is getting handed the address of the configuration information. yes, a pointer to a pointer. it's a whole chain of "no but actually." 💅
• pConfigSize — a pointer to a variable that's gonna hold the size of the ES configuration info. we love a size check.

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✨ RETURN VALUES ✨

When it goes right 🌈: *ppConfig points at a malloc'd block of memory with the ES configuration inside, and *pConfigSize tells you the number of bytes of that configuration.

When it goes wrong 😭: *ppConfig is NULL and *pConfigSize is 0. that's the vibe check failing, fr fr.

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✨ DESCRIPTION ✨

MP4GetTrackESConfiguration returns the elementary stream (ES) configuration of the track you specified in the mp4 file. lowkey important: this info is codec specific, and it holds the configuration the given codec needs in order to decode the samples in the track. no config, no decoding. periodt. 👑

Caveat, and listen closely bestie: the returned block of memory has been malloc'd. You, the caller, may safely modify the value without affecting the library — go off, customize it — BUT you take responsibility for free'ing the memory. That's your child now. You made it, you clean it up. 🫶

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✨ SEE ALSO ✨

• MP4(3) — yeah, we're linking the whole manual. it's giving "read the group chat history." 💜

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Cisco Systems Inc. made this, it's Version 0.9, and that's the whole page — mwah, love you, go free your memory. 💅✨🎀