1 @TEMPLATE decoder_tmpl.c 2 Postprocessing Decoder 3 ====================== 4 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION 5 This example adds postprocessing to the simple decoder loop. 6 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION 7 8 9 Initializing Postprocessing 10 --------------------------- 11 You must inform the codec that you might request postprocessing at 12 initialization time. This is done by passing the VPX_CODEC_USE_POSTPROC 13 flag to `vpx_codec_dec_init`. If the codec does not support 14 postprocessing, this call will return VPX_CODEC_INCAPABLE. For 15 demonstration purposes, we also fall back to default initialization if 16 the codec does not provide support. 17 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DEC_INIT 18 /* Initialize codec */ 19 res = vpx_codec_dec_init(&codec, interface, NULL, 20 VPX_CODEC_USE_POSTPROC); 21 if(res == VPX_CODEC_INCAPABLE) { 22 printf("NOTICE: Postproc not supported by %s\n", 23 vpx_codec_iface_name(interface)); 24 res = vpx_codec_dec_init(&codec, interface, NULL, 0); 25 } 26 if(res) 27 die_codec(&codec, "Failed to initialize decoder"); 28 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DEC_INIT 29 30 31 Using Adaptive Postprocessing 32 ----------------------------- 33 VP6 provides "adaptive postprocessing." It will automatically select the 34 best postprocessing filter on a frame by frame basis based on the amount 35 of time remaining before the user's specified deadline expires. The 36 special value 0 indicates that the codec should take as long as 37 necessary to provide the best quality frame. This example gives the 38 codec 15ms (15000us) to return a frame. Remember that this is a soft 39 deadline, and the codec may exceed it doing its regular processing. In 40 these cases, no additional postprocessing will be done. 41 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DECODE 42 /* Decode the frame with 15ms deadline */ 43 if(vpx_codec_decode(&codec, frame, frame_sz, NULL, 15000)) 44 die_codec(&codec, "Failed to decode frame"); 45 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DECODE 46 47 48 Codec Specific Postprocessing Controls 49 -------------------------------------- 50 Some codecs provide fine grained controls over their built-in 51 postprocessors. VP8 is one example. The following sample code toggles 52 postprocessing on and off every 15 frames. 53 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRE_DECODE 54 #if CONFIG_VP8_DECODER 55 if(frame_cnt%30 == 1) { 56 vp8_postproc_cfg_t pp = {0, 0, 0}; 57 58 if(vpx_codec_control(&codec, VP8_SET_POSTPROC, &pp)) 59 die_codec(&codec, "Failed to turn off postproc"); 60 } else if(frame_cnt%30 == 16) { 61 vp8_postproc_cfg_t pp = {VP8_DEBLOCK | VP8_DEMACROBLOCK, 4, 0}; 62 63 if(vpx_codec_control(&codec, VP8_SET_POSTPROC, &pp)) 64 die_codec(&codec, "Failed to turn on postproc"); 65 }; 66 #endif 67 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRE_DECODE 68
