#define GSM_FRAME_SIZE 160
static av_cold int libgsm_init(AVCodecContext *avctx) {
- if (avctx->channels > 1 || avctx->sample_rate != 8000 || avctx->bit_rate != 13000)
+ if (avctx->channels > 1) {
+ av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
+ avctx->channels);
return -1;
+ }
+ if (avctx->sample_rate != 8000) {
+ av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
+ avctx->sample_rate);
+ return -1;
+ }
+ if (avctx->bit_rate != 13000 /* Official */ &&
+ avctx->bit_rate != 13200 /* Very common */ &&
+ avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
+ av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
+ avctx->bit_rate);
+ return -1;
+ }
avctx->priv_data = gsm_create();