[MPlayer-dev-eng] [BUG][PATCH] Decoding of WMV3 files fail, shows only black screen

[Ivan Kalvachev]

On 7/2/05, Shachar Raindel <shacharr at gmail.com> wrote:
> Hi,
>  I have been having a problem with decoding WMV3 files, getting the
> following (interesting) messages (sorry, long post to show what is
> going on):
> <snip loads of not so interesting startup messages>
> Playing ******.wmv.
> ASF file format detected.
> VIDEO:  [WMV3]  320x240  24bpp  1000.000 fps    0.0 kbps ( 0.0 kbyte/s)
> Clip info:
>  name:
>  author:
>  copyright:
>  comments:
> ==========================================================================
> Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
> AUDIO: 44100 Hz, 2 ch, s16le, 48.0 kbit/3.40% (ratio: 6003->176400)
> Selected audio codec: [ffwmav2] afm:ffmpeg (DivX audio v2 (FFmpeg))
> ==========================================================================
> vo: X11 running at 1024x768 with depth 24 and 32 bpp (":0.0" => local display)
> ==========================================================================
> Opening video decoder: [dmo] DMO video codecs
> DMO dll supports VO Optimizations 0 1
> DMO dll might use previous sample when requested
> GetOutput r=0x0   size:230400  align:1
> StreamCount r=0x0  1  1
> Decoder supports the following formats: YV12 YUY2 UYVY YVYU RGB8
> RGB555 RGB565 RGB24 RGB32
> Decoder is capable of YUV output (flags 0x1b)
> VDec: vo config request - 320 x 240 (preferred csp: Packed YUY2)
> VDec: using Planar YV12 as output csp (no 0)
> Movie-Aspect is undefined - no prescaling applied.
> VO: [xv] 320x240 => 320x240 Planar YV12
> Selected video codec: [wmv9dmo] vfm:dmo (Windows Media Video 9 DMO)
> ==========================================================================
> Building audio filter chain for 44100Hz/2ch/s16le -> 0Hz/0ch/??...
> [libaf] setting tempo 1.000000
> alsa-init: 1 soundcard found, using: default
> alsa: 44100 Hz/2 channels/4 bpf/32768 bytes buffer/Signed 16 bit Little Endian
> AO: [alsa] 44100Hz 2ch s16le (2 bps)
> Building audio filter chain for 44100Hz/2ch/s16le -> 44100Hz/2ch/s16le...
> [libaf] setting tempo 1.000000
> Starting playback...
> ProcessInputError  FALSE ?? (keyframe: 0)
> ProcessInputError  FALSE ?? (keyframe: 0)  1/  1 ??% ??% ??,?% 1 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 1)??,?% 2 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 0)??,?% 2 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 1)??,?% 3 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 1)??,?% 3 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 1)??,?% 3 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 1)??,?% 3 0 98%
> ProcessInputError  r:0x80004005=-2147467259 (keyframe: 1)??,?% 3 0 98%
> <snip tons and tons of these messages>
> 
> Audio was playing-back great, video remained a black screen.
> What is more interesting was that seeking to the beginning of the file
> after few seconds of playback revived the video stream. After some
> messing around with DMO_VideoDecoder.c, I found out the reason: The
> first 2 calls to DMO_VideoDecoder_DecodeInternal (and therefore to the
> ProcessInput method of the DMO itself) are done with is_keyframe = 0
> (which should actually be called should_drop, and is actually rather
> redundant), since mplayer wants to drop the first frame as it is
> lagging behind the audio (it gets more audio in the beginning), and
> confuses the codec internal state, as it misses the first sync
> signals.
> 
> Removing the dependency in the phony flag of is_keyframe solved the
> problem, and now my WMV files play great.
> 
> Note that this is just a work-around, not a correct fix as the DMO now
> thinks that any bit we feed it with is a sync point (which is of
> course wrong and buggy). Someone who knows what is going on in the
> rest of this mess should fix it to provide useful information to the
> codec (probably extracted from the carrying ASF container).
> 
>    Shachar

Hi,

(the usual declaimer, i'm not win32 loader & dmo expert).

It looks like DMO interface have 2 phases. 
Phase1 - feed data into the decoder.
Phase2 - get ready data from the decoder.

To be more confusing we do hardframedrop for all small framedrops on phase1.

Probably the right way to make an soft drop is to use 
DMO_PROCESS_OUTPUT_DISCARD_WHEN_NO_BUFFER flag on 
ProcessOutput() and not supply the output buffer, as described here:
http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_c/directx/htm/imediaobjectprocessoutput.asp

Ivan Kalvachev
 iive