On Mon, 4 Feb 2019, Michael Niedermayer wrote:
On Sat, Feb 02, 2019 at 05:03:25PM +0100, Marton Balint wrote:
On Sat, 2 Feb 2019, Charles Liu wrote:
Binary searching would hang if the fragment items do NOT have timestamp for the
specified stream.
For example, a fmp4 consists of separated 'moof' boxes for each track, and
separated 'sidx' for each segment, but no 'mfra' box.
Then every fragment item only have the timestamp for one of its tracks.
I don't see why you are changing the search to be linear. Is it possible the
some of the stream fragmens have NOPTS_VALUE but other don't? In this case
you should keep the binary search and only fall back to linear search if
binary search finds an AV_NOPTS_VALUE. See similar code in function
mxf_absolute_bodysid_offset of libavformat/mxfdec.c.
The point of binary searching is to achieve O(log n) time
if there is any linear search this is no longer achieved.
So its not ideal to have any AV_NOPTS_VALUE in the array that is
searched. It would be better if the unknown entries are not in the
array that is used for the search or if their value is monotonized
once for all searches
that being ideal at least ...
Yeah that is true, but that would require maintaining a different array
with pts-es, and getting/updating fragment pts-es are complicated as is.
Considering that this fixes a hang, I'd rather see the last version of the
patch applied than wait for a more complicated, yet faster implementation.
Regards,
Marton
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