July 2011 - ffmpeg-devel - lists.ffmpeg.org

[PATCH] av_get_delay
by Nicolas George 01 Jul '11

01 Jul '11

Hi. The attached patches implement an API to get the delay of an output format. The delay is the amount of time between when a frame is fed to the format with av_write_frame and when it is actually processed by the output format. This is especially useful for devices, where this information is necessary if there is need to maintain some kind of synchronization, for example between audio and video output. I also include the test program I used to check if that works and has the expected effect: it is supposed to output two tones alternatively, and to print on the terminal when the tone change. If av_get_delay() is replaced by 0, there is a visible lag (it may be necessary to replace "default" by "hw", as "default" is usually some kind of dmix plugin, and dmix has a very short max delay). Regards, -- Nicolas George

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[PATCH] OpenAL 1.1 Capture Support
by Jonathan Baldwin 01 Jul '11

01 Jul '11

I'm not sure if I'm doing it right, but I plan to make my first contribution to any open source project right now. Attached is a patch which adds an OpenAL 1.1 audio capture input device to libavdevice. This means that audio capture in ffmpeg should now be possible on any platform with a working OpenAL 1.1 implementation. Right now, there are three major OpenAL implementations: OpenAL Soft Portable software implementation with multiple backends, currently ALSA, OSS, PulseAudio, Solaris, DirectSound, PortAudio. LGPL. Creative Creative Labs' official implementation for Windows with hardware acceleration and software fallback. Proprietary. Apple Implementation included with recent versions of Mac OS X. So far, I've only tested it on Kubuntu Linux 11.04 using the OpenAL Soft implementation, and it works great. But it should work on Windows and Mac OS X too. I'll test it on Windows if I have to (I don't have a Mac). What this code does NOT do is provide an output device for playing audio. OpenAL is more or less overkill for this anyways, as it provides a 3D audio environment. Please tell me what I can do to improve the code, after all, I am only a high school student with too much time on my hands ;-)

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[PATCH]Fix buffer size for 4bpp and 2bpp raw video
by Carl Eugen Hoyos 01 Jul '11

01 Jul '11

Hi! Attached patch fixes decoding of some 4bpp and 2bpp samples. Please comment, Carl Eugen

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[PATCH] Reinit variables for padding bugs workaround in MPEG4 streams
by Anatoly Nenashev 01 Jul '11

01 Jul '11

Hi! There is a patch in attachment which fixes the issue described in Ticket 302: https://ffmpeg.org/trac/ffmpeg/ticket/302. The problem arises in a case when the frame contains resync markers and some garbage bytes after last slice's end. The idea of solution is to reinitialize variables used in padding bugs workaround at the beginning of each frame. Regards, Anatoly.

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