The VideoLAN Forums

This is an update of a request for advice I made in Oct 2009. I have noticed others are having similar difficulties.

I am attempting to play back files on a local disk. 400-line video plays back OK, but 720-line is choppy (jumps over missing frames). Where should I look for a problem?

O/S is Windows XP Pro SP3, CPU is Pentium 4 @ 2.4 GHz, 3 GB RAM, video card Radeon X1650 Pro driving dual monitors. Playback is on primary monitor, LCD 1920x1200, 32-bit color. All graphics hardware accelerations are enabled by Windows. VLC 1.1.3 Goldeneye.

The choppiness is improved slightly by setting "Skip the loop filter for H.264 decoding" to "All", but it is still unwatchable.

When I play back the .mp4 video file, under media information, I have

Stream 0
Type: Video
Codec: avc1
Resolution: 1280x720
Display resolution 1280x720
Frame rate: 59.939820

Stream 1:
Type: Audio
Codec: mp4a
Channels: Stereo
Sample rate: 48000 Hz

And in Statistics:
Video
Decoded blocks 12548
Displayed frames 30940
Lost frames 5375
Input
Read at media 136657 kB
Input bitrate 3259 kb/s
Demuxed 13517 kB
Stream bitrate 3120 kb/s
Corrupted 0
Discontinuities 0

Turning off "Enable OSD" and "Show media title on video" improved playback. It doesn't look like 720-line resolution, but the choppiness is almost gone.

Here's what I'd like to know:

1) The loop filter directions in the FAQ do not match the UI on the 1.1.3. There are two different places in the settings that seem to match, one under FFMPEG and one under x264.
2) How do you set the decoding to use the video card's hw? I could not find this setting.
3) Does VLC make use of either multiple cores or hyperthreading to speed things up? Is this something you need to configure?
4) Any other tricks for improving H264 playback of files?

And here's what I'd like to see in future VLC releases:

A test protocol that exercises the various parts of the decoding and playback process, and tells you where the bottlenecks are, so you can upgrade the proper hw. Right now I can't tell if the slowness is due to the OS, the configuration, lack of memory, disk speed, graphics card, etc.

1) It's the FFmpeg one. x264 is the encoder only.

2) You can't on Windows XP. But for the record check here: viewtopic.php?f=14&t=79953

3) By default VLC will use all of the capabilities of your CPU.

4) Get a better and faster CPU

Your P4@2.4 GHz is a bit weak for 1280*720 @ 60 FPS.

1) It's the FFmpeg one. x264 is the encoder only.

2) You can't on Windows XP. But for the record check here: viewtopic.php?f=14&t=79953

3) By default VLC will use all of the capabilities of your CPU.

4) Get a better and faster CPU

Your P4@2.4 GHz is a bit weak for 1280*720 @ 60 FPS.

I understand (1).

For your point (2), the setting appears differently with "Simple" and "All" views. The former shows as "Use GPU acceleration (experimental)"; the latter, Input/Codecs / Video codecs / FFmpeg / Hardware decoding. At least this is my guess. If GPU accel doesn't work under XP, under which OS does it work (and do you know why)?

I am not sure I agree with (3). When VLC is running full tilt, Task Manager shows it is using about 50% CPU. I suppose it's possible the disk transfer speed is limiting, but how could I distinguish these two bottlenecks (disk or CPU)?

As far as (4), yes, I want to upgrade my hw, but to what? That's why I'd like to see a "requirements" spec, and a test hw function built in to VLC.

(2), the setting appears differently with "Simple" and "All" views. The former shows as "Use GPU acceleration (experimental)"; the latter, Input/Codecs / Video codecs / FFmpeg / Hardware decoding. At least this is my guess. If GPU accel doesn't work under XP, under which OS does it work (and do you know why)?

apperantly does not work with Windows 7 Ultimate (x64) with

HP Asus M2N68-LA Motherboard
Antec TruePower 550Watt PSU
AMD Athlon 64 X2 4800+ AM2+ 2.5GHzX2
3GB RAM(1x2GB, 1x1GB)
BFG GeForce GT220 1GB (rev.2)PCI-E x16
Western Digital 1TB 7200RPM 3.0GB/s WDC WD10 EADS-00M2B0 SCSI DD

So what, do you have to have a Ferme nVidia card for it to work? Sheesh.