diff --git a/demo.py b/demo.py
index 3cb7e75..ac6fe35 100644
--- a/demo.py
+++ b/demo.py
@@ -31,6 +31,8 @@ from utils.log import logger
 from utils.timer import Timer
 from utils.parse_config import parse_model_cfg
 import utils.datasets as datasets
+from pathlib import Path
+import tempfile
 from track import eval_seq
 
 
@@ -49,26 +51,29 @@ def track(opt):
     n_frame = 0
 
     logger.info('Starting tracking...')
-    if os.path.isdir(opt.input_video):
-        print('Use image sequence')
-        dataloader = datasets.LoadImages(opt.input_video, opt.img_size)
-        frame_rate = 30 # hack for now; see https://motchallenge.net/data/MOT16/
-    else:
-        dataloader = datasets.LoadVideo(opt.input_video, opt.img_size)
-        frame_rate = dataloader.frame_rate 
-    result_filename = os.path.join(result_root, 'results.txt')
+    
+    with tempfile.TemporaryDirectory() as tmpdirname:
+        if os.path.isdir(opt.input_video):
+            print('Use image sequence')
+            dataloader = datasets.LoadImages(opt.input_video, opt.img_size)
+            frame_rate = 30 # hack for now; see https://motchallenge.net/data/MOT16/
+        else:
+            dataloader = datasets.LoadVideo(opt.input_video, opt.img_size)
+            frame_rate = dataloader.frame_rate 
+        result_filename = os.path.join(result_root, 'results.txt')
 
-    frame_dir = None if opt.output_format=='text' else osp.join(result_root, 'frame')
-    try:
-        eval_seq(opt, dataloader, 'mot', result_filename,
-                 save_dir=frame_dir, show_image=False, frame_rate=frame_rate)
-    except Exception as e:
-        logger.info(e)
+        frame_dir = None if opt.output_format=='text' else tmpdirname
+        try:
+            eval_seq(opt, dataloader, 'mot', result_filename,
+                     save_dir=frame_dir, show_image=False, save_img=True, frame_rate=frame_rate)
+        except Exception as e:
+            logger.info(e)
 
-    if opt.output_format == 'video':
-        output_video_path = osp.join(result_root, 'result.mp4')
-        cmd_str = 'ffmpeg -f image2 -i {}/%05d.jpg -c:v copy {}'.format(osp.join(result_root, 'frame'), output_video_path)
-        os.system(cmd_str)
+        if opt.output_format == 'video':
+            name = 'result-' + Path(opt.input_video).stem + '.mp4'
+            output_video_path = osp.join(result_root, name)
+            cmd_str = 'ffmpeg -f image2 -i {}/%05d.jpg -c:v mjpeg -q:v 1 {}'.format(frame_dir, output_video_path)
+            os.system(cmd_str)
 
         
 if __name__ == '__main__':
diff --git a/track.py b/track.py
index a7804c7..3f635aa 100644
--- a/track.py
+++ b/track.py
@@ -100,7 +100,8 @@ def eval_seq(opt, dataloader, data_type, result_filename, save_dir=None, save_im
         online_targets, frame_embeddings = tracker.update(blob, img0)
         online_tlwhs = []
         online_ids = []
-        for t in online_targets:
+        # for t in online_targets:
+        for t in tracker.tracked_stracks:
             tlwh = t.tlwh
             tid = t.track_id
             vertical = tlwh[2] / tlwh[3] > 1.6
@@ -118,7 +119,7 @@ def eval_seq(opt, dataloader, data_type, result_filename, save_dir=None, save_im
         if save_dir is not None:
             base_fn = os.path.join(save_dir, '{:05d}'.format(frame_id))
             if save_img:
-                cv2.imwrite(base_fn+'.jpg', online_im)
+                cv2.imwrite(base_fn+'.jpg', online_im, [cv2.IMWRITE_JPEG_QUALITY, 100])
             if save_figures:
                 for i, fe in enumerate(frame_embeddings):
                     tlwh, curr_feat = fe