I have modified the code provided by abalta to accept bitmaps in realtime (ie you don’t already need to have the bitmaps saved to disc). It also has a performance improvement since you don’t need to write then read the bitmaps from disc. I also increased the TIMEOUT_USEC from the original example which fixed some … Read more
In a quite interesting document called H.264 Primer, a simple formula is given as an hint to compute the `ideal’ output file bitrate, based on the video’s characteristics: [image width] x [image height] x [framerate] x [motion rank] x 0.07 = [desired bitrate] where the image width and height is expressed in pixels, and the … Read more
Peace of cake! 1. Get the data As I can see, you already know how to do that (start RTSP session, SETUP a RTP/AVP/UDP;unicast; transport, and get user datagrams)… but if you are in doubt, ask. No matter the transport (UDP or TCP) the data format is mainly the same: RTP data: [RTP Header – … Read more
That just means that ffmpeg has not seen a keyframe yet, which carries SPS and PPS information. SPS and PPS are crucial in decoding an incoming frame/slice. Keyframes are sent periodically (i.e. every 5-10 seconds or more); so if it turns out that you joined a stream before the keyframe arrived; you will see this … Read more
I am going to add a late answer to this one after spending all day trying to figure out how to get YUV 4:4:4 pixels into x264. While x264 does accept raw 4:2:0 pixels in a file, it is really quite difficult getting 4:4:4 pixels passed in. With recent versions of ffmpeg, the following works … Read more
First of all: check the x264.h file, it contains more or less the reference for each function and structure. The x264.c file you can find in the download contains a sample implementation. Most people say to base yourself on that one, but I find it rather complex for beginners, it is good as an example … Read more
H.264 is a new standard for video compression which has more advanced compression methods than the basic MPEG-4 compression. One of the advantages of H.264 is the high compression rate. It is about 1.5 to 2 times more efficient than MPEG-4 encoding. This high compression rate makes it possible to record more information on the … Read more
Concepts: NALUs: NALUs are simply a chunk of data of varying length that has a NALU start code header 0x00 00 00 01 YY where the first 5 bits of YY tells you what type of NALU this is and therefore what type of data follows the header. (Since you only need the first 5 … Read more
I used these options to convert to the H.264/AAC .mp4 format for HTML5 playback (I think it may help other guys with this problem in some way): ffmpeg -i input.flv -vcodec mpeg4 -acodec aac output.mp4 UPDATE As @LordNeckbeard mentioned, the previous line will produce MPEG-4 Part 2 (back in 2012 that worked somehow, I don’t … Read more
First off, it’s important to understand that there is no single standard H.264 elementary bitstream format. The specification document does contain an Annex, specifically Annex B, that describes one possible format, but it is not an actual requirement. The standard specifies how video is encoded into individual packets. How these packets are stored and transmitted … Read more