It is not supposed to have any side effects, and the modification in question can just as well be done in filter init.
Showing the changes to libavfilter (1 of 1 file). Show all
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| @@ -91,6 +91,28 @@ static int parse_channel_name(char **arg, int *rchannel, int *rnamed) · 90 unmodified lines | ||
| 91 | 91 | return AVERROR(EINVAL); |
| 92 | 92 | } |
| 93 | 93 | |
| 94 | +static int are_gains_pure(const PanContext *pan) | |
| 95 | +{ | |
| 96 | + int i, j; | |
| 97 | + | |
| 98 | + for (i = 0; i < MAX_CHANNELS; i++) { | |
| 99 | + int nb_gain = 0; | |
| 100 | + | |
| 101 | + for (j = 0; j < MAX_CHANNELS; j++) { | |
| 102 | + double gain = pan->gain[i][j]; | |
| 103 | + | |
| 104 | + /* channel mapping is effective only if 0% or 100% of a channel is | |
| 105 | + * selected... */ | |
| 106 | + if (gain != 0. && gain != 1.) | |
| 107 | + return 0; | |
| 108 | + /* ...and if the output channel is only composed of one input */ | |
| 109 | + if (gain && nb_gain++) | |
| 110 | + return 0; | |
| 111 | + } | |
| 112 | + } | |
| 113 | + return 1; | |
| 114 | +} | |
| 115 | + | |
| 94 | 116 | static av_cold int init(AVFilterContext *ctx) |
| 95 | 117 | { |
| 96 | 118 | PanContext *const pan = ctx->priv; |
| @@ -213,6 +235,7 @@ static av_cold int init(AVFilterContext *ctx) · 116 unmodified lines | ||
| 213 | 235 | } |
| 214 | 236 | } |
| 215 | 237 | pan->need_renumber = !!nb_in_channels[1]; |
| 238 | + pan->pure_gains = are_gains_pure(pan); | |
| 216 | 239 | |
| 217 | 240 | ret = 0; |
| 218 | 241 | fail: |
| @@ -220,37 +243,14 @@ fail: · 1 unmodified line | ||
| 220 | 243 | return ret; |
| 221 | 244 | } |
| 222 | 245 | |
| 223 | −static int are_gains_pure(const PanContext *pan) | |
| 224 | −{ | |
| 225 | − int i, j; | |
| 226 | − | |
| 227 | − for (i = 0; i < MAX_CHANNELS; i++) { | |
| 228 | − int nb_gain = 0; | |
| 229 | − | |
| 230 | − for (j = 0; j < MAX_CHANNELS; j++) { | |
| 231 | − double gain = pan->gain[i][j]; | |
| 232 | − | |
| 233 | − /* channel mapping is effective only if 0% or 100% of a channel is | |
| 234 | − * selected... */ | |
| 235 | − if (gain != 0. && gain != 1.) | |
| 236 | − return 0; | |
| 237 | − /* ...and if the output channel is only composed of one input */ | |
| 238 | − if (gain && nb_gain++) | |
| 239 | − return 0; | |
| 240 | − } | |
| 241 | − } | |
| 242 | − return 1; | |
| 243 | −} | |
| 244 | − | |
| 245 | 246 | static int query_formats(AVFilterContext *ctx) |
| 246 | 247 | { |
| 247 | − PanContext *pan = ctx->priv; | |
| 248 | + const PanContext *pan = ctx->priv; | |
| 248 | 249 | AVFilterLink *inlink = ctx->inputs[0]; |
| 249 | 250 | AVFilterLink *outlink = ctx->outputs[0]; |
| 250 | 251 | AVFilterChannelLayouts *layouts; |
| 251 | 252 | int ret; |
| 252 | 253 | |
| 253 | − pan->pure_gains = are_gains_pure(pan); | |
| 254 | 254 | /* libswr supports any sample and packing formats */ |
| 255 | 255 | if ((ret = ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO))) < 0) |
| 256 | 256 | return ret; |