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POHow can I stream very long H.264 videos over HTTP without long startup times? (or: MOOV atom too large)
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copied!<p>I want to stream videos of public meetings that are often 10 hours long. Users will generally be starting at some point in the middle of the video and jumping around frequently.</p> <p>H.264 in an MP4 container seems like the current best option for encoding streaming video (right?). But these are large files -- about 1.3GB for one file -- and the metadata (MOOV atom) at the beginning of the file is itself about 40MB. If I understand correctly, clients need to download the full metadata before they're able to seek within the remainder of the file. Obviously, having to download 40MB before you can start streaming is unacceptable.</p> <p>(My tests of streaming have been with VLC and the HTML5 tag in Chrome.)</p> <p>I'm encoding the file using avconv, and am currently providing no additional settings beyond telling it which encoders to use (x264 and libfaac). I then move the metadata to the beginning of the file using qt-faststart.</p> <p>Is there a way to make the MOOV atom smaller?</p> <p>If not, are there other strategies to use (e.g. is splitting long videos into several files something that's frequently done? it seems like a real pain in terms of users seeking around the whole day's video)?</p> <p>Or should I be using a different codec or container?</p> <p>thanks!</p> <p>Here's a breakdown of the file header structure, from AtomicParsley:</p> <pre><code>Atom ftyp @ 0 of size: 32, ends @ 32 Atom moov @ 32 of size: 40157673, ends @ 40157705 Atom mvhd @ 40 of size: 108, ends @ 148 Atom iods @ 148 of size: 24, ends @ 172 Atom trak @ 172 of size: 20156304, ends @ 20156476 Atom tkhd @ 180 of size: 92, ends @ 272 Atom edts @ 272 of size: 36, ends @ 308 Atom elst @ 280 of size: 28, ends @ 308 Atom mdia @ 308 of size: 20156168, ends @ 20156476 Atom mdhd @ 316 of size: 32, ends @ 348 Atom hdlr @ 348 of size: 45, ends @ 393 Atom minf @ 393 of size: 20156083, ends @ 20156476 Atom vmhd @ 401 of size: 20, ends @ 421 Atom dinf @ 421 of size: 36, ends @ 457 Atom dref @ 429 of size: 28, ends @ 457 Atom stbl @ 457 of size: 20156019, ends @ 20156476 Atom stsd @ 465 of size: 147, ends @ 612 Atom avc1 @ 481 of size: 131, ends @ 612 Atom avcC @ 567 of size: 45, ends @ 612 Atom stts @ 612 of size: 6115608, ends @ 6116220 Atom stss @ 6116220 of size: 16960, ends @ 6133180 Atom ctts @ 6133180 of size: 5683824, ends @ 11817004 Atom stsc @ 11817004 of size: 28, ends @ 11817032 Atom stsz @ 11817032 of size: 4169724, ends @ 15986756 Atom stco @ 15986756 of size: 4169720, ends @ 20156476 Atom trak @ 20156476 of size: 20001133, ends @ 40157609 Atom tkhd @ 20156484 of size: 92, ends @ 20156576 Atom mdia @ 20156576 of size: 20001033, ends @ 40157609 Atom mdhd @ 20156584 of size: 32, ends @ 20156616 Atom hdlr @ 20156616 of size: 45, ends @ 20156661 Atom minf @ 20156661 of size: 20000948, ends @ 40157609 Atom smhd @ 20156669 of size: 16, ends @ 20156685 Atom dinf @ 20156685 of size: 36, ends @ 20156721 Atom dref @ 20156693 of size: 28, ends @ 20156721 Atom stbl @ 20156721 of size: 20000888, ends @ 40157609 Atom stsd @ 20156729 of size: 96, ends @ 20156825 Atom mp4a @ 20156745 of size: 80, ends @ 20156825 Atom esds @ 20156781 of size: 44, ends @ 20156825 Atom stts @ 20156825 of size: 9348168, ends @ 29504993 Atom stsc @ 29504993 of size: 28, ends @ 29505021 Atom stsz @ 29505021 of size: 5326296, ends @ 34831317 Atom stco @ 34831317 of size: 5326292, ends @ 40157609 Atom udta @ 40157609 of size: 96, ends @ 40157705 Atom meta @ 40157617 of size: 88, ends @ 40157705 Atom hdlr @ 40157629 of size: 33, ends @ 40157662 Atom ilst @ 40157662 of size: 43, ends @ 40157705 Atom ©too @ 40157670 of size: 35, ends @ 40157705 Atom data @ 40157678 of size: 27, ends @ 40157705 Atom free @ 40157705 of size: 8, ends @ 40157713 Atom mdat @ 40157713 of size: 1320096566, ends @ 1360254279 </code></pre>

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