Function MP3Stream_InitFromFile

code/client/cl_mp3.cpp:256–327

a file has been loaded in memory, see if we want to keep it as MP3, else as normal WAV... return = qtrue if keeping as MP3 (note: the reason I pass in the unpacked size rather than working it out here is simply because I already have it)

// (note: the reason I pass in the unpacked size rather than working it out here is simply because I already have it)
//
qboolean MP3Stream_InitFromFile( sfx_t* sfx, byte *pbSrcData, int iSrcDatalen, const char *psSrcDataFilename,
									int iMP3UnPackedSize, qboolean bStereoDesired /* = qfalse */
								)
{
	// first, make a decision based on size here as to whether or not it's worth it because of MP3 buffer space
	//	making small files much bigger (and therefore best left as WAV)...
	//

	if (cv_MP3overhead &&
			(
			//iSrcDatalen + sizeof(MP3STREAM) + FUZZY_AMOUNT < iMP3UnPackedSize
			iSrcDatalen + cv_MP3overhead->integer < iMP3UnPackedSize
			)
		)
	{
		// ok, let's keep it as MP3 then...
		//
		float fMaxVol = 128;	// seems to be a reasonable typical default for maxvol (for lip synch). Naturally there's no #define I can use instead...

		MP3_ReadSpecialTagInfo(pbSrcData, iSrcDatalen, NULL, NULL, &fMaxVol );	// try and read a read maxvol from MP3 header

		// fill in some sfx_t fields...
		//
//		Q_strncpyz( sfx->name, psSrcDataFilename, sizeof(sfx->name) );
		sfx->eSoundCompressionMethod = ct_MP3;
		sfx->fVolRange = fMaxVol;
		//sfx->width  = 2;
		sfx->iSoundLengthInSamples = ((iMP3UnPackedSize / 2/*sfx->width*/) / (44100 / dma.speed)) / (bStereoDesired?2:1);
		//
		// alloc mem for data and store it (raw MP3 in this case)...
		//
		sfx->pSoundData = (short *) SND_malloc( iSrcDatalen, sfx );
		memcpy( sfx->pSoundData, pbSrcData, iSrcDatalen );

		// now init the low-level MP3 stuff...
		//
		MP3STREAM SFX_MP3Stream = {};	// important to init to all zeroes!
		char *psError = C_MP3Stream_DecodeInit( &SFX_MP3Stream, /*sfx->data*/ /*sfx->soundData*/ pbSrcData, iSrcDatalen,
												dma.speed,//(s_khz->value == 44)?44100:(s_khz->value == 22)?22050:11025,
												2/*sfx->width*/ * 8,
												bStereoDesired
												);
		SFX_MP3Stream.pbSourceData = (byte *) sfx->pSoundData;
		if (psError)
		{
			// This should never happen, since any errors or problems with the MP3 file would have stopped us getting
			//	to this whole function, but just in case...
			//
			Com_Printf(va(S_COLOR_YELLOW"File \"%s\": %s\n",psSrcDataFilename,psError));

			// This will leave iSrcDatalen bytes on the hunk stack (since you can't dealloc that), but MP3 files are
			//	usually small, and like I say, it should never happen.
			//
			// Strictly speaking, I should do a Z_Malloc above, then I could do a Z_Free if failed, else do a Hunk_Alloc
			//	to copy the Z_Malloc data into, then Z_Free, but for something that shouldn't happen it seemed bad to
			//	penalise the rest of the game with extra alloc demands.
			//
			return qfalse;