Re: [Libav-user] Why low qmax value improve video quality?

Quantization parameter is the denominator of element-wise division. http://en.wikipedia.org/wiki/Quantization_%28image_processing%29#Quantization_matrices. So increasing QP will increase a number of lost bits of information about a picture and therefore lower image quality. 2013/9/2 theateist84

Re: [Libav-user] Different decoded frame number from ffmpeg commend line and the example demuxing

‘-r[:stream_specifier] fps (input/output,per-stream)’ Set frame rate (Hz value, fraction or abbreviation). As an input option, ignore any timestamps stored in the file and instead generate timestamps assuming constant frame rate fps. As an output option, duplicate or drop input frames to

Re: [Libav-user] Decoding single NALUs from x264 programmatically (no luck even with parser), works fine with concatenated NALUs

not - is that supposed to do the trick? Would we need a parser in that scenario? On Sun, Jul 7, 2013 at 12:13 AM, Sergey Fedorov night.rain.whis...@gmail.com wrote: Did you try using CODEC_FLAG2_CHUNKS? 2013/7/6 Attila Sukosd attila.suk...@gmail.com Hi guys, There was this thread about decoding

Re: [Libav-user] Decoding single NALUs from x264 programmatically (no luck even with parser), works fine with concatenated NALUs

Did you try using CODEC_FLAG2_CHUNKS? 2013/7/6 Attila Sukosd attila.suk...@gmail.com Hi guys, There was this thread about decoding NALUs one-by-one with parser2/decode2 and I'm having exactly the same issue. I have x264 creating a bunch of NALUs, in annex_b and repeate_headers, and

Re: [Libav-user] Format in which ES data is stored in (AVPacket*) pkt-data buffers

H.264 Video Typeshttp://msdn.microsoft.com/en-us/library/windows/desktop/dd757808%28v=vs.85%29.aspx: The MP4 container format stores H.264 data without start codes. Instead, each NALU is prefixed by a length field, which gives the length of the NALU in bytes. The size of the length field can

Re: [Libav-user] Format in which ES data is stored in (AVPacket*) pkt-data buffers

By the way, you can find the stream header in AVCodecContext::extradata after avformat_find_stream_info() call. 2013/6/14 Sergey Fedorov night.rain.whis...@gmail.com H.264 Video Typeshttp://msdn.microsoft.com/en-us/library/windows/desktop/dd757808%28v=vs.85%29.aspx: The MP4 container

Re: [Libav-user] generate encoded video file from .png files

this raw information to encoder. is it like this? /Boys21 On 11 June 2013 09:10, Sergey Fedorov night.rain.whis...@gmail.comwrote: Hi, I think you should first decode raw image data from PNG file. There is AV_CODEC_ID_PNG in libavcodec. 2013/6/10 Ramu Chakravadhanula boys21cent...@gmail.com Hi

Re: [Libav-user] generate encoded video file from .png files

You may need to use avformat_find_stream_info() too. Best wishes, Sergey 2013/6/11 Ramu Chakravadhanula boys21cent...@gmail.com okay. thanks a lot. I will give it a try and revert back if I have any troubles. Thanks and Regards, Boys21 On 11 June 2013 21:33, Sergey Fedorov

Re: [Libav-user] Getting Video Information

Hi, Try to use avformat_find_stream_info()http://ffmpeg.org/doxygen/trunk/group__lavf__decoding.html#gad42172e27cddafb81096939783b157bb . 2013/6/11 thanh nhan thanh nhan nhanndt...@yahoo.com Hi everyone, I am developing an video app using ffmpeg libs. After open video file by using

Re: [Libav-user] generate encoded video file from .png files

Hi, I think you should first decode raw image data from PNG file. There is AV_CODEC_ID_PNG in libavcodec. 2013/6/10 Ramu Chakravadhanula boys21cent...@gmail.com Hi, I have a series of png files and would like to encode them to a video file. most of the examples cover encoding a raw video

[Libav-user] Decoding H.264 SPS

Hi, I'm trying to implement hardware codec emulation by using libavcodec for doing actual coding. The hardware codec driver roughly operates as follows: 1. Send a command to decode sequence header 2. Get a stream info from the hardware 3. Knowing frame width, height, reference picture count