LibVLC empty image - c++

Question

I'm trying to use LibVLC to decode a video file and render it to a texture.
The code for opening and start playing works, the audio plays perfectly, but the pixel buffer is always filled with 0xCD. The videos I try to render work on VLC, and even in a C# implementation I did they work, but with this new code in C I can't manage to get it working...
I'm using the x64 version of the vlc libs and the program is compiled for x64 if this makes any difference.
Here is my code:
#include "stdafx.h"
#include "video.h"
#include <string.h>
#include <vlc\libvlc.h>
#include <vlc\libvlc_media.h>
#include <vlc\libvlc_media_player.h>
libvlc_instance_t* instance;
libvlc_media_t* media;
libvlc_media_player_t* player;
struct videoContext
{
unsigned char *pixeldata;
unsigned char currentFrame;
int width;
int height;
};
struct videoContext mainContext;
bool gotData = false;
int width;
int height;
static void *lock(void *data, void **p_pixels)
{
videoContext* context = (videoContext*)data;
*p_pixels = context->pixeldata;
return NULL;
}
static void unlock(void *data, void *id, void *const *p_pixels)
{
mainContext.currentFrame++;
//If I check here mainContext.pixeldata is filled with 0xCD
}
static void display(void *data, void *id)
{
}
static unsigned int formatSetup(void **opaque, char *chroma, unsigned *w, unsigned *h, unsigned *pitches, unsigned *lines)
{
chroma = "RV24";
width = *w;
height = *h;
mainContext.pixeldata = (unsigned char*)malloc(width * height * 3);
mainContext.width = width;
mainContext.height = height;
return 1;
}
void getVideoSize(int* w, int* h, int* bpp)
{
*w = width;
*h = height;
*bpp = 3 * 8;
}
videoContext* initVideo(const char* fileName)
{
mainContext.pixeldata = 0;
instance = libvlc_new(0, NULL);
media = libvlc_media_new_location(instance, fileName);
player = libvlc_media_player_new_from_media(media);
libvlc_video_set_callbacks(player, lock, unlock, display, &mainContext);
libvlc_video_set_format_callbacks(player, formatSetup, NULL);
libvlc_media_player_play(player);
return &mainContext;
}
UPDATE:
It seems that nothing is being written to the buffer as anything I set is left there.
UPDATE2:
If I remove the format setup callback and I hardcode libvlc_video_set_format with the "RV24" chroma mode and the resolution it works, so, did I understood wrongly what libvlc_video_set_format_callbacks does?
According to the documentation on the format setup callback the params can be changed to enable transcoding but even if I just leave the format as is whenever I set the format setup callback it doesn't works...

Answer 1

Ok, so, the problem was extrmely stupid. First, the pitches and lines must be set so libvlc to know the allocated sizes. Second, can't just assign chroma with a const char, it seems as the const char has an extra "\0x00" at the end liblvc counts it and then doesn't finds the decoder.
The final callback is this:
static unsigned int formatSetup(void **opaque, char *chroma, unsigned *w, unsigned *h, unsigned *pitches, unsigned *lines)
{
memcpy(chroma, "RV24", sizeof("RV24") - 1);
width = *w;
height = *h;
*pitches = width * 3;
*lines = height;
mainContext.pixeldata = (unsigned char*)malloc(width * height * 4);
mainContext.width = width;
mainContext.height = height;
return 1;
}