Questions about the data used when training Hubert

[duduke37]

When I start training using examples/hubert/README.md, first perform data preparation. Then it is said that the format of {train,valid}.tsv is.：

<root-dir>
<audio-path-1>
<audio-path-2>
...

In my understanding, that is.

But in the process of handling and training, I found that the.tsv file seems to have a value in addition to the path, such as "sz" in the following code. ：
def load_audio(manifest_path, max_keep, min_keep):
n_long, n_short = 0, 0
names, inds, sizes = [], [], []
with open(manifest_path) as f:
root = f.readline().strip()
for ind, line in enumerate(f):
items = line.strip().split("\t")
assert len(items) == 2, line
sz = int(items[1])
if min_keep is not None and sz < min_keep:
n_short += 1
elif max_keep is not None and sz > max_keep:
n_long += 1
else:
names.append(items[0])
inds.append(ind)
sizes.append(sz)
tot = ind + 1
logger.info(
(
f"max_keep={max_keep}, min_keep={min_keep}, "
f"loaded {len(names)}, skipped {n_short} short and {n_long} long, "
f"longest-loaded={max(sizes)}, shortest-loaded={min(sizes)}"
)
)
return root, names, inds, tot, sizes
So, I want to know what exactly the format of this data is. The first item is the path. What is the second item and how can it be obtained?