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I'm trying to get h.264 NAL units from a MOV file on the iPhone, in order to RTP h.264 video from the iPhone camera to a server. Apple's API does not allow direct access to the encoded bitstream from the camera output, so I can only access the MOV file, while it's being written. I've parsed the MOV file into Atoms , according to Apple's MOV structure reference but now i need to extract the NAL units from the mdat atom in order to pack it to RTP and stream it. I'd be glad for some help here because i can't find documentation about the mdat structure . Thanks! The mdat atom is a big blob of data

This question already has an answer here: Why is a conditional move not vulnerable for Branch Prediction Failure? 5 answers I'm confused where to use cmov instructions and where to use jump instructions in assembly? From performance point of view: What is the difference in both of them? Which one is better? If possible, please explain their difference with an example. Ira Baxter movcc is a so-called predicated instruction. That's fancy-speak for "this instruction executes under a condition (predicate)". Many processors, including the x86, after doing an arithmetic operation (especially compare

I have the next code: mov ax,@data mov ds,ax Why I can not write just like this? mov ds,@data All source: .MODEL small .STACK 100h .DATA HelloMessage DB 'Hello, world',13,10,'$' .CODE .startup mov ax,@data mov ds,ax mov ah,9 mov dx,OFFSET HelloMessage int 21h mov ah,4ch int 21h END Thank you! You can't, because the instruction set doesn't contain an instruction to do that. It is just one of the many idiosyncrasies of the x86. These kind of restrictions are fairly normal for assembly languages. Most architectures contain some registers that are treated specially (for example the processor

I have a set of .mov videos which require conversion to .mp4 format. I'm using ffmpeg and running this command: ffmpeg -i Banking.mov -vsync -async -sameq -ac 1 -ab 64k -ar 44100 Banking.mp4 There is a slight difference between input and output video in time length (00:03:35.407 and 00:03:35.582). And here's the catch - I'm storing time cue set at precise times in a file which is used by a program to point at specific scenes. The 0.1 second difference causes it to point at wrong scenes, therefore making the cue set useless. Is there any possibility to preserve exactly the same time in

Specifically is: mov %eax, %ds Slower than mov %eax, %ebx Or are they the same speed. I've researched online, but have been unable to find a definitive answer. I'm not sure if this is a silly question, but I think it's conceivable modifying a segmentation register could make the processor do extra work. N.B I'm concerned with old x86 linux cpus, not modern x86_64 cpus, where segmentation works differently. mov %eax, %ebx between general-purpose registers is one of the most common instructions. Modern hardware supports it extremely efficiently, often with special cases that don't apply to any