This fixes a segmentation fault because request_frame in fifo.c assumes that the call to ff_request_frame will populate fifo->root.next. Before, it was possible for request_frame in af_compand to not do this, resulting in a null pointer access. Now, request_frame in af_compand always will return at least one frame or an error, as per the API specifications in avfilter.h for request_frame.
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| @@ -71,6 +71,8 @@ typedef struct CompandContext { · 70 unmodified lines | ||
| 71 | 71 | int64_t pts; |
| 72 | 72 | |
| 73 | 73 | int (*compand)(AVFilterContext *ctx, AVFrame *frame); |
| 74 | + /* set by filter_frame() to signal an output frame to request_frame() */ | |
| 75 | + int got_output; | |
| 74 | 76 | } CompandContext; |
| 75 | 77 | |
| 76 | 78 | #define OFFSET(x) offsetof(CompandContext, x) |
| @@ -287,7 +289,15 @@ static int compand_delay(AVFilterContext *ctx, AVFrame *frame) · 210 unmodified lines | ||
| 287 | 289 | s->delay_index = dindex; |
| 288 | 290 | |
| 289 | 291 | av_frame_free(&frame); |
| 290 | − return out_frame ? ff_filter_frame(ctx->outputs[0], out_frame) : 0; | |
| 292 | + | |
| 293 | + if (out_frame) { | |
| 294 | + err = ff_filter_frame(ctx->outputs[0], out_frame); | |
| 295 | + if (err >= 0) | |
| 296 | + s->got_output = 1; | |
| 297 | + return err; | |
| 298 | + } | |
| 299 | + | |
| 300 | + return 0; | |
| 291 | 301 | } |
| 292 | 302 | |
| 293 | 303 | static int compand_drain(AVFilterLink *outlink) |
| @@ -559,9 +569,11 @@ static int request_frame(AVFilterLink *outlink) · 265 unmodified lines | ||
| 559 | 569 | { |
| 560 | 570 | AVFilterContext *ctx = outlink->src; |
| 561 | 571 | CompandContext *s = ctx->priv; |
| 562 | − int ret; | |
| 572 | + int ret = 0; | |
| 563 | 573 | |
| 564 | − ret = ff_request_frame(ctx->inputs[0]); | |
| 574 | + s->got_output = 0; | |
| 575 | + while (ret >= 0 && !s->got_output) | |
| 576 | + ret = ff_request_frame(ctx->inputs[0]); | |
| 565 | 577 | |
| 566 | 578 | if (ret == AVERROR_EOF && s->delay_count) |
| 567 | 579 | ret = compand_drain(outlink); |