[MPlayer-users] per-frame seeking in AVI files

Arpi arpi at thot.banki.hu
Wed Feb 6 00:45:02 CET 2002


Hi,

> | again. tricky, ehh?
> | (and of course it was forward only)
> | <snip>
> | as mjpeg files have keyframes at every frame, it is possible to implement.
> 
> I see--clever!. So, a related question: would it be at all feasible for MPlayer
> to enable forwards and backwards playback if keyframes are detected at every
> frame, or just if playing back an MJPEG movie? Without synced sound, of course.

yes. it's already on our too long TODO list. near to its end...

> | > Also, it was mentioned that the A-V sync was thrown off; was this true for AVI
> | > files as well as MPEGs?
> | for everything.
> | audio is buffered, and keep it sync with single frames played at
> | unpredictable speed and direction is a very bit hard.
> 
> Okay; would it be possible to disable buffering in a case where we want to do
> these seeks, and would that make it easier? I'm probably speaking nonsense
> here, since at the moment I'm unfamiliar with MPlayer's internals; a change
> like this is probably very fundamental.

audio buffering is made at 3 places: demuxer, codec and soundcard.
we cannot control soundcard, cannot seek backward in demuxer and depending
on audio format, maybe we cannot control buffering of codec.
so it's near to impossible.

for short term backward seek, we could perserve last N seconds of decoded
audio, keep resetting audio device and with some luck and well working audio
driver it may work...  anyway i don't know what is 40ms audio chunk playback
good for. you'll hear only ticks, no sound...


A'rpi / Astral & ESP-team

--
"I don't RTFM? Wow. What's the meaning of this? It's new for me."
	-- Martin Baum, a tipical MPlayer user...




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