Hi All,
I've been writing apps using libavcodec for several years without problem.
I recently wrote an app which pulls MPEG2 packets from satellite and decodes
them with the software MPEG2VIDEO codec (CODEC_ID_MPEG2VIDEO).
Everything works great.
So now I want to take advantage of VDPAU (mainboard chipset = NVIDIA GeForce
8200 mGPU)
All I changed in my code was this one line:
From: gCodec = avcodec_find_decoder(CODEC_ID_MPEG2VIDEO);
To: gCodec = avcodec_find_decoder_by_name("mpegvideo_vdpau");
avcodec_init();
avcodec_register_all();
// find the mpeg2 video decoder
gCodec = avcodec_find_decoder_by_name("mpegvideo_vdpau");
if (!gCodec) {
fprintf(stderr, "codecInit: Codec not found: mpegvideo_vdpau\n");
return 1;
}
gContext = avcodec_alloc_context();
gPicture = avcodec_alloc_frame();
gContext->workaround_bugs = FF_BUG_AUTODETECT;
gContext->error_concealment = FF_EC_GUESS_MVS;
gContext->error_recognition = FF_ER_CAREFUL;
gContext->thread_count = 2;
if (avcodec_open(gContext, gCodec) < 0) {
fprintf(stderr, "codecInit: Could not open codec\n");
return 1;
}
...
<fill "inbuf" with MPEG2 compressed>
...
len = avcodec_decode_video(gContext, gPicture, &got_picture, inbuf, size);
if (len < 0) {
fprintf(stderr, "codecDecode: Error while decoding frame %u\n",
frame_num);
return 1;
}
if (got_picture) ...
And I get a segment fault:
Program received signal SIGSEGV, Segmentation fault.
0x081e4b55 in ff_vdpau_mpeg_picture_complete (s=0x8d78b30, buf=0x861f200 "\217",
buf_size=13667, slice_count=0) at libavcodec/vdpauvideo.c:187
187 render = (struct vdpau_render_state*)s->current_picture_ptr->data[0];
(gdb) bt
#0 0x081e4b55 in ff_vdpau_mpeg_picture_complete (s=0x8d78b30, buf=0x861f200
"\217",
buf_size=13667, slice_count=0) at libavcodec/vdpauvideo.c:187
#1 0x08217b68 in decode_chunks (avctx=0x8d786c0, picture=0x8d78a50,
data_size=0xbffff6a0,
buf=0x861f200 "\217", buf_size=13667) at libavcodec/mpeg12.c:2317
#2 0x08218570 in mpeg_decode_frame (avctx=0x8d786c0, data=0x8d78a50,
data_size=0xbffff6a0,
buf=0x861f200 "\217", buf_size=13667) at libavcodec/mpeg12.c:2289
#3 0x0805529e in avcodec_decode_video (avctx=0x8d786c0, picture=0x8d78a50,
got_picture_ptr=0xbffff6a0, buf=0x861f200 "\217", buf_size=13667) at
libavcodec/utils.c:508
#4 0x08050e9c in codecDecode (frame_num=1, inbuf=0x861f200 "\217", size=13667)
at tsplay.c:446
#5 0x080510d4 in frameRender (frame_num=1, inbuf=0x861f200 "\217",
inbuf_size=13667)
at tsplay.c:540
#6 0x08050983 in main (argc=2, argv=0xbffff804) at tsplay.c:189
(gdb) list
182 int buf_size, int slice_count)
183 {
184 struct vdpau_render_state * render, * last, * next;
185 int i;
186
187 render = (struct vdpau_render_state*)s->current_picture_ptr->data[0];
188 assert(render);
189
190 /* fill VdpPictureInfoMPEG1Or2 struct */
191 render->info.mpeg.picture_structure = s->picture_structure;
So, I'm assuming that I have to do something different to use the vdpau version
of the MPEG2 codec?
What's the magic?
Any tips or pointers would be greatly appreciated!
Thanks,
Bob
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