diff options
| -rw-r--r-- | libhb/common.c | 91 |
1 files changed, 34 insertions, 57 deletions
diff --git a/libhb/common.c b/libhb/common.c index 93c98ffa4..6d4d5ee5e 100644 --- a/libhb/common.c +++ b/libhb/common.c @@ -710,74 +710,51 @@ float hb_get_default_audio_compression( uint32_t codec ) return compression; } -int hb_get_best_mixdown( uint32_t codec, int layout, int mixdown ) +int hb_get_best_mixdown(uint32_t codec, int layout, int mixdown) { - int best_mixdown; - + if (codec & HB_ACODEC_PASS_FLAG) { - // Audio pass-thru. No mixdown. + // Audio passthrough, no mixdown return HB_AMIXDOWN_NONE; } - switch (layout & ~AV_CH_LOW_FREQUENCY) + else if ((layout & AV_CH_LAYOUT_5POINT1) == AV_CH_LAYOUT_5POINT1 || + (layout & AV_CH_LAYOUT_5POINT1_BACK) == AV_CH_LAYOUT_5POINT1_BACK) { - // mono input - case AV_CH_LAYOUT_MONO: - best_mixdown = HB_AMIXDOWN_MONO; - break; - - // Dolby Pro Logic (a.k.a. Dolby Surround), 4.0 channels (matrix-encoded) - // The A52 flags don't allow for a way to distinguish between DPL1 and - // DPL2 on a DVD so we always assume a DPL1 source for A52_DOLBY. - case AV_CH_LAYOUT_STEREO_DOWNMIX: - // 3 or 4 discrete channels - case AV_CH_LAYOUT_2_1: - case AV_CH_LAYOUT_2_2: - case AV_CH_LAYOUT_QUAD: - case AV_CH_LAYOUT_4POINT0: - case AV_CH_LAYOUT_SURROUND: - // a52dec and libdca can't upmix to 6ch, so we must downmix these. - // libdca only supports DPLII if the source is 3F2R to begin with. - best_mixdown = HB_AMIXDOWN_DOLBY; - break; - - // 5 to 8 discrete channels - case AV_CH_LAYOUT_5POINT0: - case AV_CH_LAYOUT_7POINT0: - if (!(layout & AV_CH_LOW_FREQUENCY)) - { - // we don't do 5-channel discrete - // a52dec and libdca can't upmix to 6ch, so we must downmix this. - best_mixdown = HB_AMIXDOWN_DOLBYPLII; - } - else - { - switch (codec) - { - case HB_ACODEC_LAME: - case HB_ACODEC_FFAAC: - best_mixdown = HB_AMIXDOWN_DOLBYPLII; - break; - - default: - best_mixdown = HB_AMIXDOWN_6CH; - break; - } - } - break; - - // stereo input or something not handled above - default: - // mono gets mixed up to stereo & more than stereo gets mixed down - best_mixdown = HB_AMIXDOWN_STEREO; - break; + // full 3F2R, possibly with additional channels, and an LFE + // limiting factor: liba52, libdca (can't upmix) + best_mixdown = HB_AMIXDOWN_6CH; + } + else if ((layout & AV_CH_LAYOUT_5POINT0) == AV_CH_LAYOUT_5POINT0 || + (layout & AV_CH_LAYOUT_5POINT0_BACK) == AV_CH_LAYOUT_5POINT0_BACK) + { + // full 3F2R, possibly with additional channels, but no LFE + // limiting factor: liba52, libdca (can't upmix) + // limiting factor: libdca (can only do DPL2 with 3F2R sources) + best_mixdown = HB_AMIXDOWN_DOLBYPLII; + } + else if(layout == AV_CH_LAYOUT_STEREO) + { + // limiting factor: no Dolby Surround for Stereo sources + best_mixdown = HB_AMIXDOWN_STEREO; } + else if(av_get_channel_layout_nb_channels(layout) == 1) + { + // only one channel, not much point in upmixing + best_mixdown = HB_AMIXDOWN_MONO; + } + else + { + // everything else, including Dolby (AV_CH_LAYOUT_STEREO_DOWNMIX) + best_mixdown = HB_AMIXDOWN_DOLBY; + } + // return the best that is not greater than the requested mixdown // 0 means the caller requested the best available mixdown - if( best_mixdown > mixdown && mixdown > 0 ) + if (best_mixdown > mixdown && mixdown > 0) best_mixdown = mixdown; - + return best_mixdown; } |