[FFmpeg-devel] calculation of probe score

[Monique Lassere]

Hi, all,

Trying to dig as deeply as possible into ffprobe's probe score and how it
is calculated. AVProbeData
<https://www.ffmpeg.org/doxygen/2.2/structAVProbeData.html> contains a lot
of specific information about the tags and signatures ffprobe uses to
identify various formats. However, I have noticed some issues that
AVProbeData does not seem to address (in my novice ability to read C):

1. Even if ffprobe does not find a codec ID for a given stream, it can
still attempt to identify the stream. What type of information does ffprobe
use to guess the stream?

2. Secondly, does the probe score relate to the container format only? From
my look at AVProbeData and the test results I've gotten, that's what it
looks like: an example is a report from a Matroska file with an identified
H.264 encoding (lacking an identifiable tag) achieving a score of 100, and
many others. Therefore, it seems like ffprobe only returns a lower probe
score if data is missing from the container format.

Thanks for any thoughts or input.

Best,

Monique Lassere

M.S. Candidate in Library & Information Science, UIUC
Graduate Assistant at Research & Information Services
Graduate Hourly at the Rare Book & Manuscript Library
Format Registry Manager at Digital Bedrock
LinkedIn <https://www.linkedin.com/in/moniquelassere> || 847-361-0047