av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode, unsigned int *sample_rate, int channels, enum CodecID *codec_id) { AlsaData *s = ctx->priv_data; const char *audio_device; int res, flags = 0; snd_pcm_format_t format; snd_pcm_t *h; snd_pcm_hw_params_t *hw_params; snd_pcm_uframes_t buffer_size, period_size; int64_t layout = ctx->streams[0]->codec->channel_layout; if (ctx->filename[0] == 0) audio_device = "default"; else audio_device = ctx->filename; if (*codec_id == CODEC_ID_NONE) *codec_id = DEFAULT_CODEC_ID; format = codec_id_to_pcm_format(*codec_id); if (format == SND_PCM_FORMAT_UNKNOWN) { av_log(ctx, AV_LOG_ERROR, "sample format 0x%04x is not supported\n", *codec_id); return AVERROR(ENOSYS); } s->frame_size = av_get_bits_per_sample(*codec_id) / 8 * channels; if (ctx->flags & AVFMT_FLAG_NONBLOCK) { flags = SND_PCM_NONBLOCK; } res = snd_pcm_open(&h, audio_device, mode, flags); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot open audio device %s (%s)\n", audio_device, snd_strerror(res)); return AVERROR(EIO); } res = snd_pcm_hw_params_malloc(&hw_params); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot allocate hardware parameter structure (%s)\n", snd_strerror(res)); goto fail1; } res = snd_pcm_hw_params_any(h, hw_params); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot initialize hardware parameter structure (%s)\n", snd_strerror(res)); goto fail; } res = snd_pcm_hw_params_set_access(h, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set access type (%s)\n", snd_strerror(res)); goto fail; } res = snd_pcm_hw_params_set_format(h, hw_params, format); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set sample format 0x%04x %d (%s)\n", *codec_id, format, snd_strerror(res)); goto fail; } res = snd_pcm_hw_params_set_rate_near(h, hw_params, sample_rate, 0); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set sample rate (%s)\n", snd_strerror(res)); goto fail; } res = snd_pcm_hw_params_set_channels(h, hw_params, channels); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set channel count to %d (%s)\n", channels, snd_strerror(res)); goto fail; } snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size); buffer_size = FFMIN(buffer_size, ALSA_BUFFER_SIZE_MAX); /* TODO: maybe use ctx->max_picture_buffer somehow */ res = snd_pcm_hw_params_set_buffer_size_near(h, hw_params, &buffer_size); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set ALSA buffer size (%s)\n", snd_strerror(res)); goto fail; } snd_pcm_hw_params_get_period_size_min(hw_params, &period_size, NULL); if (!period_size) period_size = buffer_size / 4; res = snd_pcm_hw_params_set_period_size_near(h, hw_params, &period_size, NULL); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set ALSA period size (%s)\n", snd_strerror(res)); goto fail; } s->period_size = period_size; res = snd_pcm_hw_params(h, hw_params); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "cannot set parameters (%s)\n", snd_strerror(res)); goto fail; } snd_pcm_hw_params_free(hw_params); if (channels > 2 && layout) { if (find_reorder_func(s, *codec_id, layout, mode == SND_PCM_STREAM_PLAYBACK) < 0) { char name[128]; av_get_channel_layout_string(name, sizeof(name), channels, layout); av_log(ctx, AV_LOG_WARNING, "ALSA channel layout unknown or unimplemented for %s %s.\n", name, mode == SND_PCM_STREAM_PLAYBACK ? "playback" : "capture"); } if (s->reorder_func) { s->reorder_buf_size = buffer_size; s->reorder_buf = av_malloc(s->reorder_buf_size * s->frame_size); if (!s->reorder_buf) goto fail1; } } s->h = h; return 0; fail: snd_pcm_hw_params_free(hw_params); fail1: snd_pcm_close(h); return AVERROR(EIO); }