What causes "Out of memory.\n" in DrKLO/Telegram?

Reduce input length or downsample before comparing so nframes stays small.

Out of memory.\n

Error message

Out of memory.\n

What it means

Generic out-of-memory sentinel from opus_compare's allocator wrappers. check_alloc() is called by opus_malloc() and opus_realloc() throughout the comparison utility; if malloc/realloc returns NULL it prints this and calls exit(EXIT_FAILURE). This kills the whole process — there is no recovery.

Source

Thrown at TMessagesProj/jni/opus/src/opus_compare.c:40

   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>

#define OPUS_PI (3.14159265F)

#define OPUS_COSF(_x)        ((float)cos(_x))
#define OPUS_SINF(_x)        ((float)sin(_x))

static void *check_alloc(void *_ptr){
  if(_ptr==NULL){
    fprintf(stderr,"Out of memory.\n");
    exit(EXIT_FAILURE);
  }
  return _ptr;
}

static void *opus_malloc(size_t _size){
  return check_alloc(malloc(_size));
}

static void *opus_realloc(void *_ptr,size_t _size){
  return check_alloc(realloc(_ptr,_size));
}

static size_t read_pcm16(float **_samples,FILE *_fin,int _nchannels){
  unsigned char  buf[1024];
  float         *samples;
  size_t         nsamples;
  size_t         csamples;

View on GitHub (pinned to 45ab8f4308)

Solutions

Reduce input length or downsample before comparing so nframes stays small.
Stream/chunk the comparison instead of allocating all frames at once.
Free other process memory before running; increase the machine's RAM/swap.
Validate file sizes via read_pcm16's returned length and bail before the big allocations if unreasonably large.

Example fix

// before (whole-file allocation can exhaust memory on long inputs)
xb=(float *)opus_malloc(nframes*NBANDS*nchannels*sizeof(*xb));

// after: cap nframes and process in windows
if (nframes > MAX_FRAMES_IN_MEM) { fprintf(stderr,"Input too long for in-memory compare; chunk it.\n"); return EXIT_FAILURE; }
xb=(float *)opus_malloc(nframes*NBANDS*nchannels*sizeof(*xb));

Defensive patterns

Strategy: validation

Validate before calling

// Cap nframes before the large allocations.
if (nframes > MAX_FRAMES_IN_MEM) {
    fprintf(stderr, "Input too long (%zu frames) for in-memory compare\n", nframes);
    return EXIT_FAILURE;
}

Prevention

Trim or downsample long recordings before comparing.
Chunk the comparison instead of allocating all frames at once.
Free other process memory or add swap before running on large inputs.

When it happens

Trigger: Any opus_malloc/opus_realloc call in opus_compare returns NULL. The largest allocations are the per-band/per-frequency coefficient arrays (xb, X, Y) sized nframes*NBANDS/NFREQS*nchannels. Very long input files make nframes huge, exploding the allocation.

Common situations: Comparing two very long .sw recordings so nframes (and thus xb/X/Y) overflows available memory; comparing many-channel files; running on a memory-limited CI box; a malformed file reporting a huge sample count.

Related errors

AI-assisted analysis of DrKLO/Telegram@45ab8f4308 (2026-08-14). Data as JSON: /api/errors/3267ff24a53de4ec. Report an issue: GitHub.