Status
()
People
(Reporter: jya, Unassigned)
Tracking
(Blocks: 2 bugs)
Firefox Tracking Flags
(Not tracked)
Details
Attachments
(1 attachment)
32.46 KB,
audio/mp4
|
Details |
Created attachment 8917008 [details]
segment0.m4a
$ mp4dump.exe ~/Downloads/segment0.m4a
[ftyp] size=8+12
major_brand = isom
minor_version = 200
compatible_brand = isom
[moov] size=8+651
[mvhd] size=12+96
timescale = 1000
duration = 0
duration(ms) = 0
[trak] size=8+365
[tkhd] size=12+80, flags=3
enabled = 1
id = 1
duration = 4294967295
width = 0.000000
height = 0.000000
[mdia] size=8+265
[mdhd] size=12+20
timescale = 44100
duration = 4294967295
duration(ms) = 97391548
language = unk
[hdlr] size=12+33
handler_type = soun
handler_name = SoundHandler
[minf] size=8+180
[smhd] size=12+4
balance = 0
[dinf] size=8+28
[dref] size=12+16
[url ] size=12+0, flags=1
location = [local to file]
[stbl] size=8+120
[stsd] size=12+40
entry-count = 1
[.mp3] size=8+28
data_reference_index = 1
[stts] size=12+4
entry_count = 0
[stsc] size=12+4
entry_count = 0
[stsz] size=12+8
sample_size = 0
sample_count = 0
[stco] size=12+4
entry_count = 0
[mvex] size=8+64
[trex] size=12+20
track id = 1
default sample description index = 1
default sample duration = 0
default sample size = 0
default sample flags = 0
[trex] size=12+20
track id = 2
default sample description index = 1
default sample duration = 0
default sample size = 0
default sample flags = 0
[udat] size=8+90
So we can see using mp4dump that the file has a duration set in both the track header (tkhd) and media header (mdhd) is set. the movie header has a duration set at 0.
The rust mp4 demuxer returns a duration of 0 for this file. It shouldn't
(Reporter) | ||
Updated•a year ago
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Flags: needinfo?(ayang)
Comment 1•a year ago
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According to spec 14496-12 A.8 Fragmented movie files, "However the Movie Box does not contain the information for the full duration of the movie". And the duration 4294967295 is 0xFFFFFFFF, do you really want demuxer return it?
Flags: needinfo?(ayang)
(Reporter) | ||
Comment 2•a year ago
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(In reply to Alfredo Yang (:alfredo) from comment #1) > According to spec 14496-12 A.8 Fragmented movie files, "However the Movie > Box does not contain the information for the full duration of the movie". I think you're misreading the spec... the introduction to this section is: "This section introduces a technique that may be used in ISO files, where the construction of a single Movie Box in a movie is burdensome." This only indicates that the duration may not been set in the MOOV... It doesn't state that if it is known it shouldn't be used. > > And the duration 4294967295 is 0xFFFFFFFF, do you really want demuxer return > it? yes, this is a perfectly valid duration :) stagefright logic was to use the mvhd duration if present, if not max(tkhd's duration) That's what MP4Metadata code does, except that here the rust demuxer always return 0 for all of those.
Priority: -- → P3
Priority: P3 → P2
Comment 3•a year ago
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Hi, I think it is a good first bug to familiar with mp4 rust codes.
Flags: needinfo?(cchang)
Updated•a year ago
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Assignee: ayang → attach-and-request
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Description
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